CA2083284A1 - Firearm insert for firing smaller caliber ammunition and a process for producing an insertable barrel - Google Patents
Firearm insert for firing smaller caliber ammunition and a process for producing an insertable barrelInfo
- Publication number
- CA2083284A1 CA2083284A1 CA002083284A CA2083284A CA2083284A1 CA 2083284 A1 CA2083284 A1 CA 2083284A1 CA 002083284 A CA002083284 A CA 002083284A CA 2083284 A CA2083284 A CA 2083284A CA 2083284 A1 CA2083284 A1 CA 2083284A1
- Authority
- CA
- Canada
- Prior art keywords
- barrel
- insertable
- ammunition
- insert
- loading shell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
- B21C37/15—Making tubes of special shape; Making tube fittings
- B21C37/152—Making rifle and gunbarrels
- B21C37/153—Making tubes with inner- and/or outer guides
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F41—WEAPONS
- F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
- F41A21/00—Barrels; Gun tubes; Muzzle attachments; Barrel mounting means
- F41A21/10—Insert barrels, i.e. barrels for firing reduced calibre ammunition and being mounted within the normal barrels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F41—WEAPONS
- F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
- F41A21/00—Barrels; Gun tubes; Muzzle attachments; Barrel mounting means
- F41A21/16—Barrels or gun tubes characterised by the shape of the bore
- F41A21/18—Grooves-Rifling
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B8/00—Practice or training ammunition
- F42B8/02—Cartridges
- F42B8/10—Cartridges with sub-calibre adaptor
Abstract
ABSTRACT
The insert consists of an insertable barrel (27) and a loading shell (21). The ratio of the dimension of the inside to the outside of the insertable barrel (27) amounts to more than 60%
in the case of an inside diameter of less than 5 mm, and its outer side is completely smooth so that it fits accurately into the bore of the rifle that is to be used. The associated loading shell (21) consists of two separable parts (1, 10).
The ammunition (7) of smaller diameter that is to be used can be inserted into the front, female part (1). The rear, male part (10) contains a firing pin (11) that can move axially in a drilling that is incorporated in this part. The rear part (10) of the loading shell is inserted into the front part (1) and secured by means of a bayonet lock. The outside shape of the assembled loading shell (21) that is provided with a charge (7) corresponds to that of a conventional rifle cartridqe for the particular firearm and can be handled in the same way as such a cartridge. In particular, a plurality of loading shells (21) can be loaded into the rifle magazine, and reloading requires only a manual loading movement. The grooves (28) and the lands (29) in the insertable barrel (27) according to the present invention are produced by means of a cold-forming process, in that hammers that are arranged around the periphery of a stationary core that extends to the whole length of the barrel (27) form a standard tube, while the barrel (27) that has been produced is withdrawn from the core, under the hammers, whilst being appropriately rotated.
The insert consists of an insertable barrel (27) and a loading shell (21). The ratio of the dimension of the inside to the outside of the insertable barrel (27) amounts to more than 60%
in the case of an inside diameter of less than 5 mm, and its outer side is completely smooth so that it fits accurately into the bore of the rifle that is to be used. The associated loading shell (21) consists of two separable parts (1, 10).
The ammunition (7) of smaller diameter that is to be used can be inserted into the front, female part (1). The rear, male part (10) contains a firing pin (11) that can move axially in a drilling that is incorporated in this part. The rear part (10) of the loading shell is inserted into the front part (1) and secured by means of a bayonet lock. The outside shape of the assembled loading shell (21) that is provided with a charge (7) corresponds to that of a conventional rifle cartridqe for the particular firearm and can be handled in the same way as such a cartridge. In particular, a plurality of loading shells (21) can be loaded into the rifle magazine, and reloading requires only a manual loading movement. The grooves (28) and the lands (29) in the insertable barrel (27) according to the present invention are produced by means of a cold-forming process, in that hammers that are arranged around the periphery of a stationary core that extends to the whole length of the barrel (27) form a standard tube, while the barrel (27) that has been produced is withdrawn from the core, under the hammers, whilst being appropriately rotated.
Description
2~8~28~
A FIREARM INSERT FOR FIRING SMALLER CALIBRE AMMUNITION AND A
PROCESS FOR PRODUCING AN INSERTABLE BARREL
The present invention relates to an insert for a firearm, for example, for a rifle sr a hand-held weapon, by means of ~hich it is possible to fire ammunition of a smaller calibre than that for which the particular firearm is designed. In addition, a further object of the present invention is a process by means of which it is possible to produce the insertable barrel that is associated with this insert. Such inserts are mainly used in large-calibre rifles or hand-held weapons for purposes of training, so that the shooter can practice firing and aiming at shorter ranges. In addition, this s~all-calibre ammunition is less costly, and when it is fired, it generates far less noise compared to the noise lS generated by large-calibre ammunition. Thus, there is a great demand for such inserts for firearms training. Firing small-calibre ammunition is particularly well suited to training novice shooters, for they can become accustomed to handling large-calibre firearms and can gain experience in aiming and delivering fire. Firearms training that is conducted by using such inserts is less costly or, given the same costs, is more efficient, for more ammunition can be fired. In addition, firing that is conducted using ammunition of this calibre is not governed by particular regulations so that it is not always necessary to visit a rifle range; rather, such shooting can be conducted in open terrain, for example, in a forest or in open fields~ as well as in private property, when large-calibre firearms can be used to fire such ammunition.
Typically, using 4 mm ammunition, which is commercially available under the designation M20, shooting is carried out at a range of 10 m.
Several versions of inserts of this kind that are used for large-calibre firearms are found in the prior art. Towards the end of the 1930s, the so-càlled Lienhard insert was developed for the Swiss carbine, and this can also be fitted to the Swiss Model S7 assault rifle, which is of the same calibre as the carbine. This Lienhard insert includes an insertable barrel and a loading shell. The barrel insert consists of a tube with an outside diameter that is the same as the calibre of the rifle barrel, which is to say it has a S diameter of 7.~ mm for this particular rifle. Two circular grooves, spaced apart along the length of the insertable barrel, are machined into its outer surface and a cord packing or an o~ring of flexible rubber material is installed in each of these. The insertable barrel has an i~side diameter that amounts to at least 4 mm overall. Grooves that are 0.15 mm deep are machined out of the inner side of the insertable barrel, and these extend to the whole length of the barrel and twist through one-quarter of a turn. ~he inside diameter between two opposite grooves thus amounts to 4.3 mm, and to 4 mm between two opposing lands. A 4-mm caliber projectile that i~ ~ired through the barrel, and which in point of fact has a diameter of 4.3 mm, is pressed into the grooves and the spiral path of th2 lands located between the grooves will then impart a spin to the projectile, which stabilizes its trajectory.
When it is used, the ~ienhard insertable barrel is inserted into the barrel of the particular rifle from the breech end.
Then the associated Lienhard loading shell is made ready.
Essentially, this consists of a hollow cylinder, the projectile that is to be fired being installed at the front end of this and a cap that is separated from the projectile is installed on the rear end. When the weapon is fired, the firing pin of the rifle bolt strikes the base of the cap and the resulting explosion acts through the loading shell and drives the projectile through the bore of the barrel. In order to re load, the loading shell has to be removed from the chamber, which is inconvenient, and the expended cap has to be removed from it by using a pusher pin~ Then, the loading shell has to be refitted with a projectile and a cap, and inserted into the barr~l once again. For this reason, re-loading requires time-consuming manipulation. A loading shell that consists of two separable parts could also be used with the Lienhard insert. At its front end, the foremost of these accepted the projectile that was to be fired and behind this 2~3~
the charge which is separated from the projectile, the cap.
After the two parts had been assembled the rear part was clamped to the base of the cap by means of a screw, so that a blow on the rear end of the loading shell was transmitted through the base of the cap, which caused the charge to detonate.
The so-called Walter insertable barrel is an alternative to this. Externally, this has the same shape as a GPll rifle cartridge which can be fired both from the carbine and from ~he Nodel 57 assault rifle. It is 70 mm long and has a continuous axial bore of 4 ~m diameter, within which helical grooves are machined, with the result that the diameter between two grooves amounts to 4.3 mm. Externally, this insertable barrel which, in a way, is formed by the cartridge itself, has two circular grooves in which flexible rubber 0-rings are installed. The Walter insertable barrel is loaded in that the ammunition is inserted into the rear end. The ammunition thak is to be fired consists of a cartridge case that is joined direckly to the projectile, which is of 4.3 mm ~iameter, and which is known by the designation M20. Several such Walter insertable barrels can be stored in a magazine in the same way as actual rifle cartridges. On loading, such an insertable barrel is loaded in the chamber and the weapon is fired when the firing pin of the rifle bolt which, in an actual rifle cartridge strikes the base of the cartridge, now strikes the base of the cartridge case of the M20 ammunition that has be~n inserted. The projectile is then driven through the bore o~ the barrel and discharged, when, once again, a spin is imparted to it. The disadvantage o~ this insertable barrel is the fact that it is held in the chamber of the rifle only by means of the flexible rubber O-rings. Because of the constant re-insPrtion, positioning becomes relatively imprecise, and thus considerable dispersion of the shots is unavoidable. Thus, accuracy leaves much to be desired. In addition, if the trainee shooter does not wish to remove the magazine after each shot~ in order to load the cartridges that are combined with the insertable barrel, then he has to buy a 2~328~
number of such complete insertable barrels. Then, the can prepare all of these and load them into the magazine, after which he can fire the individual charges one after the other.
All that is needed is to complete a loading movement between the individual shots. The procurement of a number ~f such complete insertable barrels is, however, very costly.
Another solution for firing training ~sing large-calibre rifles is offered by the ri~le insert that has become known as the C02 insert, which was developed for short-range firing with the new Swiss Model 90 assault rifle, which can be procured commercially under the designation EP90. This rifle insert consists of a breech piece into which a commercially available C02 cartridge can be inserted, this being of the 1~ sort, for example, that is used to fill rechargeable soda-water syphons. A projectile with a calibre of 5.5 mm is fired using this rifle insert, and this equals the actual calibre of this weapon. In point of fact, the projectiles may be of a slightly larger diameter in order to take more of the deviations that can result from continuous firing into account. In order to fire the weapon with the C02 insert, a projectile of this kind is loaded into the chamber of the rifle, and this is then pressed forward into the bore by a loading movement of the specially constructed breech piece, in which a C02 cartridge has previously been inserted. The breech piece incorporates a mechanism so that when the trigger is operated, the valve of the ro2 cartridge is abruptly opened and the pressure acts on the projectile that is accommodated in the bore. A disadvantage of this insert is mainly that the muzzle velocity of the projectile that can be achieved is too low to achieve any great measure of accuracy. For this reason, aiming must be carried out with a special addition to the existing sighting system, which takes into account the relatively low muzzle velocity of the projectile by imparting a greater angle of elevation to the rifle.
Up to the present, there has been no insert that makes it possible to fire M20 4-mm centre fire ammunition as training 20~32~4 ammunition for the Model ~0 assault ri~le, or the Model EP90 assault rifle, which have a calibre of 5.5 mm, and would provide accuracy comparable to that achieved with the Lienhard insert. This is attributable to the technical problem that it is impossible to machine grooves into a bore of 4 mm inside diameter and with an outside diameter of only 5.5 mm. ~he barrel would be badly distorted or even destroyed by the machining forces that are generated. It is true that an insertable barrel of this kind can be produced in that one first machines the grooves into a 4 mm bore with a larger outside diameter, and subsequently turns the outside diameter down to the desired dimension. However, such a process is much too costly. First, six to twelve passes are required to cut out grooves that are approximately 0.15 mm deep. In the 15 case of a barrel with the usual eight grooves, this results in an extremely high number of machine passes that have to be completed, which entails enormously high machining costs.
Second, the barrel becomes distorted and, for this reason, has to be straightened subsequently. Third, its outside diameter has to be turned down to the desired dimension. In order to avoid high machining forces, it is only possible to remove an extremely thin layer during each pass, for which reason, once again, a large number of machining steps are required. An insertable barrel produced in this way would become so costly that there would hardly be any chance of selling it. In many rifle barrels, very frequently the grooves are not machined out but rather the barrel is cold formed around an appropriate core. It is the opinion of the professional community that this cold forming is impossible in the case of such small diameters as a 4-mm insertable barrel for use in a firearm with a calibre of 5.5 mm, because the material would split.
For the technical reasons set out above, up to now it has been impossible to obtain an insert for the Model 90 assault rifle, which includes an insertable barrel and which would actually be insertable into the barrel of this rifle even though such an insertable barrel would satisfy a very large demand. In addition, there is no loading shell for M20 centre fire 2~8328~
ammunition, which is the only effective type and which requires a minimum of manipulation during re-loading.
For this reason, it is the task of the present invention to S create an insert for firearms to fire reduced-calibre ammunition using a weapon of larger calibre, in particular for the Model 90 assault rifle or comparable weapons, which makes it possible to achieve greater accuraGy and which requires the simplest possible manipulation for re-loading. In addition, 0 it iS al80 a task of the present invention to describe a procegs for manufacturing the associated insertable barrel.
The present invention solves this task by using an insert for firearms, which are used to fire ammunition of smaller calibre than that for which the particular weapon is designed, with an insertable barrel and a loading shell that is of two separable parts, and which is characterized in that at an inside diameter of the insertable barrel of less than 5 mm, the ratio of the dimension of its insîde to its outside diameter is more than 60%; and in that a one-piece munition consisting of a cartridge case and a projectile can be inserted into the foremost part of the loading shell, a firing pin being so supported in its rearmost part so as to be moveable in an axial direction.
In addition, the present invention solves this problem by means of a process for manufacturing an insertable barrel for this insert that is characterized in that the grooves and the lands in the bore are produced in the barrel by means of cold forging from the inner side of the tube of a greater outside and inside diameter than the barrel that is to be produced, in that a plurality of hammers that are arranged peripherally around the tube act radially and simultaneously on its outside diameter and against its stationary core, which is located within it and which has the negative shape of the appropriate grooves and lands, the tube being drawn off the core beneath the hammers whilst being appropriately rotated, after which the outside is turned down and fine finished.
2~3~8~
~ The insert according to the present invention makes it ; possible to fire ammunition of a reduced calibre using firear~s that are designed for larger calibre ammunition. ~he S loading shell of the insert according to the present inYention can be loaded into the conventional magazine of the firearm and ~anipulated in exactly the same way as the ammunition for which the weapon is designed. In particular, a magazine that has been filled can be emptied shot by shot when all that is required betwee~ the shots is a manual loading movement. When this i~ done, the loading shell is automatically ejected, in exactly the same way as a spent rifle cartridge case. The particular production process for the associated insertable barrel permits production that is so cost-effective that, for the first time, an insertable barrel that can actually be inserted into the rifle barrel can be offered for sale.
Furthermore, the insertable barrel according to the present invention is of such superior precision that the effectiveness of firing training with surh small-calibre ammunition can be very grea~ly increased. Tests have shown that the dispersion pattern achieved at a range of 20 m is sufficient to render it effective to practice at this range.
An embodiment of the invention is shown in the drawings appended hereto and described in the followiny description with reference to the drawings. These drawings shown the following:
Figure 1: the front part of the loading shell in longitudinal cross part, with ammunition inserted in it, and to the right of this a view of the same loading shell part from behind;
Figure 2: the rear part of the loading shell with the firing pin, in longitudinal cross section, and to the right of this a view of this part of the loading shell from the front;
Figure 3: the loading shell with the ammunition prior to assembly, in a perspective view;
2~8~28~
Figure 4: the assembled loading shell when loaded at th~
moment of firing, in longitudinal cross section, and beneath this a conventional rifle cartridge for purposes of comparison; Figure 5: the insertable barrel in longitudinal cross section with the loading shell adjacent to it;
Figures 6a to 6d: the process for producing the insertable barrel at three point~ of the~process, and the finished insartable barrel, each in longitudinal section.
The insert according to the present invention consists of a specially developed loadin~ shell and of an insertable barrel produced by a unique, specially developed process. These two elements of the insert are matched to each other and together for~ the underlying con~ept of the present invention, in that they work in conjunction with each other. Figure 1 is a longitudinal cross section through the front part 1 of the loading shell that ~orms part of the insert and this, according to the present invention, is configured in two parts. This front p~rt 1 of the loading shell is essentially a hollow cylinder that forms a female part for the rear part ~f the loading shell~ Its outside diameter matches to a large extent that o~ a conventional rifle cartridge in its front axea, so that this front part 1 of the loading shell fits into the appropriate cartridge chamber of the firearm. The inner side consists of sections of di~ferent diameters. In the rearmost area 2, the inside diameter is greatest, and this is then followed by an area 3 of a somewhat smaller inside diameter; finally there is another area 4 with an inside diameter that is even smaller~ Ad3acent to this, in the area of the foremost opening, there is a funnel-shaped tapered section 5 that finally makes a transmission to become the actual opening 6 with the smallest inside diameter. The ammunition 7 that is to be fired fits into this funnel-shaped area 5, 6 of the opening area of the front part 1 of the loading shell, and this ammunition then protxudes somewhat from the front of the loading shell itself. The ammunition 7 can be inserted there in that it is pushed into the front part 2~g328~
:
1 of the loading shell from behind and is then held by a positive shape fit in the opening area 5, 6, as is shown in figure 1. In practice, when it is loaded, the front part 1 of the loading shell is held vertical so that the largest inside S diameter is on top, whereupon the ammunition 7 can be dropped into this foremost part ~ of the loading shell. The right-hand drawing in figure 1 shows the front part of the loading shell as viewed fxom the rear. Viewed together with the longitudinal section, it can be seen that the area 3 that ha~
the ~econd largest diameter has two opposing areas of smaller diameter 8 at the rear; these extend through approximately 90 of the periphery and are opposite each other. This means that the recesses 9 are formed, as can be seen in the view from behind. These recesses 9 or the areas 8 of smaller diameter are part of a bayonet catch, as will be explained below.
Figure 2 shows the male part 10 that can be inserted into the female part 1 that is shown in figure 1, which has just been described. This male or rear part 10 of the loading shell according to the present invention also forms a hollow cylinder with which a firing pin 11 is supported and guided in an axial direction, and which has an appropriately small diameter. This firing pin 11 is additionally guided at the rear by means of a guide sleeve 12 which also prevents it from falling out of the loading shell. It has a thickened section 13 in its middle area, and this is somewhat shorter than the corresponding recess 14 in the inside wall of the hollow cylinder, so that the thickened portion 13 is guided in this recess 14, al$hough the firing pin 11 can be moved through a specific range of movement in an axial direction. The firing pin 11 is of an equal length to the total rear part lo of the loading shell. At the front, this firing pin has a rounded tip 15 that is intended to strike the base of the cap of the ammunition. Externally, the rear part 16 of the male loading 3s shell part 10 is shaped so as to be identical of the shape of a conventional rifle cartridge. Thus, it has a projecting rim 15 that is created by appropriate recesses 18 and which is intended to work as a stop for the ejector on the bolt of the 2~3~8~
weapon. The front part 19 of the male loading shell part 10 has outside diameters that are the same as the associated inside diameters of the female front part l of the loading shell shown in figure 1. In particular, it has two thickened S sections ~0 that similarly extend for approximately 90 around the periphery and when rotated appropriately with respect to the front part 1 of the loading shell these correspond to the recesses 9 in this. To the right of ~he longitudinal section that is shown in figure 2 there is a front view of the male loading shell part 10, in which these two thickened areas 20 can ~e seen.
Figure 3 is a perspective view of the loading shell 21 with the ammunition 7 that is to be inserted into it, this showing the loading shell before assembly. This drawing shows the female front part 1 and the male rear part 10 of the loading shell 21. In the area l9 of the rear part 10 there are the two sections with different diameters, and the thicker areas 20 which form part of the bayonet catch. At the rear end of the rear part 10 of the loading shell 21 there is the rim 17 that is required to eject the loading shell 21 after the ammunition has been fired. Between the two parts 1, 10 of the loading shell 21 there is the ammunition 7, as it is to be inserted into the front part 1 of the loading shell 21. This consists of a cartridge case 22 and a 4~mm projectile 23 that is installed on the front end of the cartridge case 22. After the loading shell 21 has been assembled, the projectile 23 and the front edge of the cartridge case 22 extend from the drilling in the front part of the loading shell 21.
Pigure 4 shows the two parts 1, 10 of the loading shell 21 as assembled just prior to firing. The male rear part 10 of the loading shell 21 is inserted into the female front part 1 after the ammunition has been installed. To this end, the two parts l, 10 have to be rotated relative to each other so that the thickened portions 20 on the rear part 10 enter the recesses 9 in the front part 1. It is only when in this rotated position that the two parts 1, 10 can be inserted 2~28~
one into the other. After this, they are secured against coming apart by being rotated, when the thickened parts 20 on the rear part 10 rotate over the corresponding narrow sections 8 on the front part 1 in the manner of a bayonet catch when S they come to a solid stop on this. Because of a slight slope to the surfaces of the thickened parts 20 that lie against each other, or similar slope on the narrower portions 8 on the two parts 1, 10 the rotation of the parts 1, 10 relative to each other results in increasing friction, which then prevents the parts 1, 10 from rotating and being loosened. In this position, when they are inserted into each other, the front end of the male loading shell part 1 presses the ammunition 7 into ths funnel-shaped recess 5, 6 in the area of the opening of the front loading shell part 1. Of course, other means ~5 could be used to connect the two parts 1, 10. For example, it would also be possible to use a threaded connection, so that the t~o parts could be screwed together. If the loading shell that has been assembled and loaded in this manner is now inserted into the weapon, and if the trigger of the weapon is operated, the firing pin of the rifle bolt strikes the firing pin 11 inside the loading shell 21, and the tip 15 of this then, in its turn, strikes the base of the ammunition 7 and causes the charge within it to explode. The loaded and prepared loading shell 21 that is shown in figure 4 can be handled in exactly the same way as a conventional rifle cartridge. For purposes of comparison, a conventional rifle cartridge 25 is shown beneath the drawing of the loading shell 21 in its assembled state, and it can be seen that the dimensions of this cartridge 25 are identical to those of the loading shell 21 up to and including the projectile 26 that extends from the front of the loading shell. Thus, a plurality of loading shells 21 that have been prepared in this way can be loaded into the magazine of the weapon and a loading movement of the rifle bolt will expel this loading shell 21 in exactly the same way as the spent casing of a conventional rifle cartridge, even if the loading movement of the bolt has not been initiated by the pressure generated by 2~3~8~
the explosion of the ammunition that is fired, but rather by manual operation.
Up to now, only the loading shell 21 of the insert has bsen S described. Using thi~ loading shell 21, it is possible to fire ammunition of a calibre that is smaller than that for which the rifle barrel has been designed. The second element o~ the insert according to the present invention is thus an insertable barrel that can be inserted into the existing barrel of the ~irearm, thereby reducing the inside diameter or calibre of this. What is particularly difficult in respect to the insertable barrel for the Model ~0 assault rifle is the fact that the calibre of this rifle is not much greater than that of the small-calibre ammunition that is to be fired. Its ~5 calibre is 5.5 ~m, whereas the smaller-calibre ammunition that is to be fired, which is designated M20 centre fire ammunition, has a diameter of 4 mm. The wall thickness of an insertable barrel that is suitable for this purpose and which is intended ~or insertion into the conventional barrel of the Model 90 assault rifle, as is designated EP90, is thus unavoidably extremely thin.
Figure 5 is a longitudinal cross section through an insertable barrel 27 of this kind, and it also shows the associated loading shell 21 with the ammunition 7. In order to fire M20 centre fire ammunition, this insertable barrel has an inside diameter of 4 mm measured across the grooves, whereas the inside diameter measured across the lands is 4.3 mm. For this reason, the ratio of the dimension of the inner to the outer diameter of the insertable barrel 26 amounts to more than 60%, in comparison to that of the Lienhard insertable barrel, in which this ratio is clearly under 60~ for the same ammunition.
The grooves 2~ and the lands 29, which twist through 90 along the length of the barrel, are shown on the inner side of the insertable barrel. At the breech end 30, the insertable barrel 27 has a small thicker area 31 and the end edge 32 is funnel-shaped on the outside. The projectile 23 of the ammunition 7 is located at the funnel-shaped opening 5 of the 2~32~
insertable barrel 27 when the weapon is loaded, as can be seen from figure 5. The remaining outer side 33 of the insertable barrel 26, which is adjacent to the thickened section 31, is machined so as to be smooth along its whole length and thus S ha~ neither raised nor depressed sections.
It is a particular technical problem to create the required grooves 28 and lands 29 in such a thi~-walled insertable barrel 27, such that production costs can be kept within 10 acceptable limits. It is impossible to machine out the individual grooves 28 with subsequent honing and lapping of the barrel because of the high production costs discussed above. The costs that are associated with this would be unacceptable. In addition, every barrel would have to be lS subsequently straightened because the reaction forces of such processing would unavoidably twist it. In view of this problem, the pre~ent invention has created a process which treads a completely new path for such small bore diameters, in that the grooves 28 and the lands 29 are formed on the inside of the bore by means of cold forming of the barrel 27 about an appropriately-shaped core that is at least as long as the length of the barrel. Grooves 28 and lands 29 are already ~orged in rifle barrels by cold ~orming about a core.
However, the cores that are used to do this are only a few centimetres lon~, and never as long as the rifle barrel itself. During the shaping process they are held under tension on the core by a tapered extension which extends to the whole length of the barrel whilst the barrel is drawn off the core, under the hammers that are used in the shaping process. After ~orming, the barrels are straightened since they are unavoidably bent during the forming process. The smaller the barrel diameters, the more the distortion that has to be expected. In addition, straightening would be too costly for small insertable barrels. Expert opinion is that the production o~ an insertable barrel with a diameter that is clearly much smaller is impossible using the known process for cold forming, for this would unavoidably destroy the thin-wall materialO In contrast to this, the present invention creates 2~8328~
a process for producing grooves 28 and lands 29 in an insertable barrel 27 having such a small inside diameter, by means of cold forming, in that the barrel is hammered over a core that matches the negative shape of the desired inside of S the barrel and which extends to the whole length of the barrel. A core that is configured in this way, and i8 of high speed steel, will always provide the barrel with the required stability when it is being ~haped by ~he hammers, so that no distortion takes place and it thus becomes unnecessary to straighten the barrels subsequently. Three different stages in the process according to the present invention are ~hown in figures 6a to 6c, and ~igure 6d shows the finished insertable barrel. For purposes of clarity, the insertable barrels in figures 6a to 6d are all shown in one cross section. For an lS insertable barrel that is 110 mm long, for example, and which is intended for insertion into the Swiss Model 90 assault rifle, a standard tube 34 with an outside diameter of 11 mm and an inside diameter of 5 mm is used. This tube 34, which, for purposes of forming, should advantageously have a length of at least approximately 180 mm, is installed over a core 35 of high-speed steel that is approximately 150 mm long. From one end 36, the outside of this core 35 corresponds to the negative form of eight grooves 28 and eight lands 29 to a length of at least llO mm, and these make one-quarter turn along this length of 110 mm.
Figure 6a shows the situation at the beginning of the cold forming process. The standard tube 34 is installed completely over that part of the core 35 that has the grooves 28 and the lands 29. The unattached end 37 is clamped into a shaping machine, by means of which it can be withdrawn in an axial direction whilst the core 35 is ~eing rotated. The core 35, in its turn, is clamped firmly by its unattached end 38. The hammers 39 work in the same stationary location with reference to the core 35. At the start of the process, as is shown in figure 6a, the hammers 39 strike the outer side of one end of what is to be the insertable barrel. It is advantageous that the eight hammers 39 strike simultaneously, these eight 2~3~8~
hammers 39 being arranged equidistantly about the periphery sf the standard tube 34, and each strikes the outer surface in a radial direction. Every pair of hammers 39 is opposite each other, 80 that the striking forces that they generate act opposite to each other and ~hereby cancel each other out. It is advantageous that the hammers 39 have striking surfaces that are curved concavely so as to be an approximate match to the outsid~ surface of the tube. Duri~g the ha~mering process, the tube is now drawn slowly off the core 35 and at the same time a rotational movement is superimposed on this axial movement, this corresponding to the turns of the grooves 28 ~nd the lands 29 with reference to their negative shape on the coxe 35. Shortly after this, the situation is as depicted in figure 6b, in which the tube 34 has been withdrawn from 1~ approximately half the core length, so that about half of what is to be the barrel has already been formed. The forming can be seen by the taper of the tube 34 in the area 27 that has already been processed. This processing is continued until finally the tube 34 is drawn off the core 35, as is shown in figure 6c. Given the dimensions that are shown in this example, the outside diameter of the tube 34 is tapered by approximately 2 mm by the hammer blows, this resulting in a new outside diameter of approximately 9 mm. However, the outside diameter of the insertable barrel 27 must be so small that the insertable barrel 27 fits into the rifle barrel. In the case of the Model 90 assault rifle, the internal diameter is 5.5 mm measured over the lands. However, this diameter becomes somewhat larger, i.e., at the mid-point by about 3 to 6/lOOths mm, once a certain number of shots have passed through the barrel. The outside diameter of the insertable barxel 27 is now finished to this final dimension, in that it is first turned down to an outside diameter of 5.7 mm. A
thickened area, of which the edge 32 is funnel-shaped on the outside, is left in place right at the bolt end. Finally, the outside diameter is fine-machined to a dimension of 5.56 mm, after which the insertable barrel 27 is cut to the desired length, in the exampl~ shown to 110 mm, so that it ultimately appears as shown in figure 6d. The finished insertable barrel 2~28l~
is shown in longitudinal section in figure 6d. The accuracy of an insertable barrel 27 that is produced in this way is so - high that the tolerance of the inside diameter to its length of 110 ~m does not exceed l/lOOth mm in the present example.
S The hots that are fired from it are correspondingly accurate.
In order to determine the dispersal accuracy of a rifle, it is first clamped into position and 10 shots are fired from it.
The total of the points scored is a metric for the precision of the particular rifle. Rifles ~hich, when fired at a range of 300 m at an A-type target, with 10 rings, achieve a point score of 96 with 10 such ~hots are considered as first-rate firearms in knowledgeable circles, and can be offered for sale as such. Firing is conducted at 10 m using the correspondingly smaller target with 10 divisions, as used for small-calibre weapons. Tests have shown that a Model 90 assault rifle fitted with the insert according to the present invention, and firing M20 centre fire ammunition at a 70 m range can achieve a 100 shot image, which is to say a total point score of 100 when fired at a No. 10 disk (as a dispersal pattern). Becau~e of its outstanding precision, the insert according to the present invention is best suited for small-arms training. Firing as well as aiming can be practised very economically, at a level of effectiveness that has been unachievable up to now. The rifle can be converted very simply by installing the insertable barrel 27 in the breech end opening of the barrel. After firing ammunition of a smaller calibre using the insert according to the present invention the rifle can be reconverted for normal operation in that the insertable barrel 27 is pushed out of the barrel using a plastic rod which is inserted into the barrel from the muzzle end. It is, of course, understood that the insert according to the present invention can be produced for a large number of rifles or even pistols and revolvers by using the appropriate dimensions. The only condition is that the outside diameter of the associated insertable barrel be matched to the calibre of the rifle or hand-held weapon that is to be used and the loading shell correspond to a normal rifle cartridge for the particular firearm, in relation to its external 2~3~8'~
dimensions. For this reason, and in particular, it is possible to produce an insert for the Swiss Model 57 assault rifle and the Swiss carbine. Then, the insertable barrel will have an outside diameter of 7.55 mm and the exterior of the S associated two-part loading shell will correspond to the rifle cartridge 11 that is usually fired from this weapon.
: . ~ , , ,. . : .
A FIREARM INSERT FOR FIRING SMALLER CALIBRE AMMUNITION AND A
PROCESS FOR PRODUCING AN INSERTABLE BARREL
The present invention relates to an insert for a firearm, for example, for a rifle sr a hand-held weapon, by means of ~hich it is possible to fire ammunition of a smaller calibre than that for which the particular firearm is designed. In addition, a further object of the present invention is a process by means of which it is possible to produce the insertable barrel that is associated with this insert. Such inserts are mainly used in large-calibre rifles or hand-held weapons for purposes of training, so that the shooter can practice firing and aiming at shorter ranges. In addition, this s~all-calibre ammunition is less costly, and when it is fired, it generates far less noise compared to the noise lS generated by large-calibre ammunition. Thus, there is a great demand for such inserts for firearms training. Firing small-calibre ammunition is particularly well suited to training novice shooters, for they can become accustomed to handling large-calibre firearms and can gain experience in aiming and delivering fire. Firearms training that is conducted by using such inserts is less costly or, given the same costs, is more efficient, for more ammunition can be fired. In addition, firing that is conducted using ammunition of this calibre is not governed by particular regulations so that it is not always necessary to visit a rifle range; rather, such shooting can be conducted in open terrain, for example, in a forest or in open fields~ as well as in private property, when large-calibre firearms can be used to fire such ammunition.
Typically, using 4 mm ammunition, which is commercially available under the designation M20, shooting is carried out at a range of 10 m.
Several versions of inserts of this kind that are used for large-calibre firearms are found in the prior art. Towards the end of the 1930s, the so-càlled Lienhard insert was developed for the Swiss carbine, and this can also be fitted to the Swiss Model S7 assault rifle, which is of the same calibre as the carbine. This Lienhard insert includes an insertable barrel and a loading shell. The barrel insert consists of a tube with an outside diameter that is the same as the calibre of the rifle barrel, which is to say it has a S diameter of 7.~ mm for this particular rifle. Two circular grooves, spaced apart along the length of the insertable barrel, are machined into its outer surface and a cord packing or an o~ring of flexible rubber material is installed in each of these. The insertable barrel has an i~side diameter that amounts to at least 4 mm overall. Grooves that are 0.15 mm deep are machined out of the inner side of the insertable barrel, and these extend to the whole length of the barrel and twist through one-quarter of a turn. ~he inside diameter between two opposite grooves thus amounts to 4.3 mm, and to 4 mm between two opposing lands. A 4-mm caliber projectile that i~ ~ired through the barrel, and which in point of fact has a diameter of 4.3 mm, is pressed into the grooves and the spiral path of th2 lands located between the grooves will then impart a spin to the projectile, which stabilizes its trajectory.
When it is used, the ~ienhard insertable barrel is inserted into the barrel of the particular rifle from the breech end.
Then the associated Lienhard loading shell is made ready.
Essentially, this consists of a hollow cylinder, the projectile that is to be fired being installed at the front end of this and a cap that is separated from the projectile is installed on the rear end. When the weapon is fired, the firing pin of the rifle bolt strikes the base of the cap and the resulting explosion acts through the loading shell and drives the projectile through the bore of the barrel. In order to re load, the loading shell has to be removed from the chamber, which is inconvenient, and the expended cap has to be removed from it by using a pusher pin~ Then, the loading shell has to be refitted with a projectile and a cap, and inserted into the barr~l once again. For this reason, re-loading requires time-consuming manipulation. A loading shell that consists of two separable parts could also be used with the Lienhard insert. At its front end, the foremost of these accepted the projectile that was to be fired and behind this 2~3~
the charge which is separated from the projectile, the cap.
After the two parts had been assembled the rear part was clamped to the base of the cap by means of a screw, so that a blow on the rear end of the loading shell was transmitted through the base of the cap, which caused the charge to detonate.
The so-called Walter insertable barrel is an alternative to this. Externally, this has the same shape as a GPll rifle cartridge which can be fired both from the carbine and from ~he Nodel 57 assault rifle. It is 70 mm long and has a continuous axial bore of 4 ~m diameter, within which helical grooves are machined, with the result that the diameter between two grooves amounts to 4.3 mm. Externally, this insertable barrel which, in a way, is formed by the cartridge itself, has two circular grooves in which flexible rubber 0-rings are installed. The Walter insertable barrel is loaded in that the ammunition is inserted into the rear end. The ammunition thak is to be fired consists of a cartridge case that is joined direckly to the projectile, which is of 4.3 mm ~iameter, and which is known by the designation M20. Several such Walter insertable barrels can be stored in a magazine in the same way as actual rifle cartridges. On loading, such an insertable barrel is loaded in the chamber and the weapon is fired when the firing pin of the rifle bolt which, in an actual rifle cartridge strikes the base of the cartridge, now strikes the base of the cartridge case of the M20 ammunition that has be~n inserted. The projectile is then driven through the bore o~ the barrel and discharged, when, once again, a spin is imparted to it. The disadvantage o~ this insertable barrel is the fact that it is held in the chamber of the rifle only by means of the flexible rubber O-rings. Because of the constant re-insPrtion, positioning becomes relatively imprecise, and thus considerable dispersion of the shots is unavoidable. Thus, accuracy leaves much to be desired. In addition, if the trainee shooter does not wish to remove the magazine after each shot~ in order to load the cartridges that are combined with the insertable barrel, then he has to buy a 2~328~
number of such complete insertable barrels. Then, the can prepare all of these and load them into the magazine, after which he can fire the individual charges one after the other.
All that is needed is to complete a loading movement between the individual shots. The procurement of a number ~f such complete insertable barrels is, however, very costly.
Another solution for firing training ~sing large-calibre rifles is offered by the ri~le insert that has become known as the C02 insert, which was developed for short-range firing with the new Swiss Model 90 assault rifle, which can be procured commercially under the designation EP90. This rifle insert consists of a breech piece into which a commercially available C02 cartridge can be inserted, this being of the 1~ sort, for example, that is used to fill rechargeable soda-water syphons. A projectile with a calibre of 5.5 mm is fired using this rifle insert, and this equals the actual calibre of this weapon. In point of fact, the projectiles may be of a slightly larger diameter in order to take more of the deviations that can result from continuous firing into account. In order to fire the weapon with the C02 insert, a projectile of this kind is loaded into the chamber of the rifle, and this is then pressed forward into the bore by a loading movement of the specially constructed breech piece, in which a C02 cartridge has previously been inserted. The breech piece incorporates a mechanism so that when the trigger is operated, the valve of the ro2 cartridge is abruptly opened and the pressure acts on the projectile that is accommodated in the bore. A disadvantage of this insert is mainly that the muzzle velocity of the projectile that can be achieved is too low to achieve any great measure of accuracy. For this reason, aiming must be carried out with a special addition to the existing sighting system, which takes into account the relatively low muzzle velocity of the projectile by imparting a greater angle of elevation to the rifle.
Up to the present, there has been no insert that makes it possible to fire M20 4-mm centre fire ammunition as training 20~32~4 ammunition for the Model ~0 assault ri~le, or the Model EP90 assault rifle, which have a calibre of 5.5 mm, and would provide accuracy comparable to that achieved with the Lienhard insert. This is attributable to the technical problem that it is impossible to machine grooves into a bore of 4 mm inside diameter and with an outside diameter of only 5.5 mm. ~he barrel would be badly distorted or even destroyed by the machining forces that are generated. It is true that an insertable barrel of this kind can be produced in that one first machines the grooves into a 4 mm bore with a larger outside diameter, and subsequently turns the outside diameter down to the desired dimension. However, such a process is much too costly. First, six to twelve passes are required to cut out grooves that are approximately 0.15 mm deep. In the 15 case of a barrel with the usual eight grooves, this results in an extremely high number of machine passes that have to be completed, which entails enormously high machining costs.
Second, the barrel becomes distorted and, for this reason, has to be straightened subsequently. Third, its outside diameter has to be turned down to the desired dimension. In order to avoid high machining forces, it is only possible to remove an extremely thin layer during each pass, for which reason, once again, a large number of machining steps are required. An insertable barrel produced in this way would become so costly that there would hardly be any chance of selling it. In many rifle barrels, very frequently the grooves are not machined out but rather the barrel is cold formed around an appropriate core. It is the opinion of the professional community that this cold forming is impossible in the case of such small diameters as a 4-mm insertable barrel for use in a firearm with a calibre of 5.5 mm, because the material would split.
For the technical reasons set out above, up to now it has been impossible to obtain an insert for the Model 90 assault rifle, which includes an insertable barrel and which would actually be insertable into the barrel of this rifle even though such an insertable barrel would satisfy a very large demand. In addition, there is no loading shell for M20 centre fire 2~8328~
ammunition, which is the only effective type and which requires a minimum of manipulation during re-loading.
For this reason, it is the task of the present invention to S create an insert for firearms to fire reduced-calibre ammunition using a weapon of larger calibre, in particular for the Model 90 assault rifle or comparable weapons, which makes it possible to achieve greater accuraGy and which requires the simplest possible manipulation for re-loading. In addition, 0 it iS al80 a task of the present invention to describe a procegs for manufacturing the associated insertable barrel.
The present invention solves this task by using an insert for firearms, which are used to fire ammunition of smaller calibre than that for which the particular weapon is designed, with an insertable barrel and a loading shell that is of two separable parts, and which is characterized in that at an inside diameter of the insertable barrel of less than 5 mm, the ratio of the dimension of its insîde to its outside diameter is more than 60%; and in that a one-piece munition consisting of a cartridge case and a projectile can be inserted into the foremost part of the loading shell, a firing pin being so supported in its rearmost part so as to be moveable in an axial direction.
In addition, the present invention solves this problem by means of a process for manufacturing an insertable barrel for this insert that is characterized in that the grooves and the lands in the bore are produced in the barrel by means of cold forging from the inner side of the tube of a greater outside and inside diameter than the barrel that is to be produced, in that a plurality of hammers that are arranged peripherally around the tube act radially and simultaneously on its outside diameter and against its stationary core, which is located within it and which has the negative shape of the appropriate grooves and lands, the tube being drawn off the core beneath the hammers whilst being appropriately rotated, after which the outside is turned down and fine finished.
2~3~8~
~ The insert according to the present invention makes it ; possible to fire ammunition of a reduced calibre using firear~s that are designed for larger calibre ammunition. ~he S loading shell of the insert according to the present inYention can be loaded into the conventional magazine of the firearm and ~anipulated in exactly the same way as the ammunition for which the weapon is designed. In particular, a magazine that has been filled can be emptied shot by shot when all that is required betwee~ the shots is a manual loading movement. When this i~ done, the loading shell is automatically ejected, in exactly the same way as a spent rifle cartridge case. The particular production process for the associated insertable barrel permits production that is so cost-effective that, for the first time, an insertable barrel that can actually be inserted into the rifle barrel can be offered for sale.
Furthermore, the insertable barrel according to the present invention is of such superior precision that the effectiveness of firing training with surh small-calibre ammunition can be very grea~ly increased. Tests have shown that the dispersion pattern achieved at a range of 20 m is sufficient to render it effective to practice at this range.
An embodiment of the invention is shown in the drawings appended hereto and described in the followiny description with reference to the drawings. These drawings shown the following:
Figure 1: the front part of the loading shell in longitudinal cross part, with ammunition inserted in it, and to the right of this a view of the same loading shell part from behind;
Figure 2: the rear part of the loading shell with the firing pin, in longitudinal cross section, and to the right of this a view of this part of the loading shell from the front;
Figure 3: the loading shell with the ammunition prior to assembly, in a perspective view;
2~8~28~
Figure 4: the assembled loading shell when loaded at th~
moment of firing, in longitudinal cross section, and beneath this a conventional rifle cartridge for purposes of comparison; Figure 5: the insertable barrel in longitudinal cross section with the loading shell adjacent to it;
Figures 6a to 6d: the process for producing the insertable barrel at three point~ of the~process, and the finished insartable barrel, each in longitudinal section.
The insert according to the present invention consists of a specially developed loadin~ shell and of an insertable barrel produced by a unique, specially developed process. These two elements of the insert are matched to each other and together for~ the underlying con~ept of the present invention, in that they work in conjunction with each other. Figure 1 is a longitudinal cross section through the front part 1 of the loading shell that ~orms part of the insert and this, according to the present invention, is configured in two parts. This front p~rt 1 of the loading shell is essentially a hollow cylinder that forms a female part for the rear part ~f the loading shell~ Its outside diameter matches to a large extent that o~ a conventional rifle cartridge in its front axea, so that this front part 1 of the loading shell fits into the appropriate cartridge chamber of the firearm. The inner side consists of sections of di~ferent diameters. In the rearmost area 2, the inside diameter is greatest, and this is then followed by an area 3 of a somewhat smaller inside diameter; finally there is another area 4 with an inside diameter that is even smaller~ Ad3acent to this, in the area of the foremost opening, there is a funnel-shaped tapered section 5 that finally makes a transmission to become the actual opening 6 with the smallest inside diameter. The ammunition 7 that is to be fired fits into this funnel-shaped area 5, 6 of the opening area of the front part 1 of the loading shell, and this ammunition then protxudes somewhat from the front of the loading shell itself. The ammunition 7 can be inserted there in that it is pushed into the front part 2~g328~
:
1 of the loading shell from behind and is then held by a positive shape fit in the opening area 5, 6, as is shown in figure 1. In practice, when it is loaded, the front part 1 of the loading shell is held vertical so that the largest inside S diameter is on top, whereupon the ammunition 7 can be dropped into this foremost part ~ of the loading shell. The right-hand drawing in figure 1 shows the front part of the loading shell as viewed fxom the rear. Viewed together with the longitudinal section, it can be seen that the area 3 that ha~
the ~econd largest diameter has two opposing areas of smaller diameter 8 at the rear; these extend through approximately 90 of the periphery and are opposite each other. This means that the recesses 9 are formed, as can be seen in the view from behind. These recesses 9 or the areas 8 of smaller diameter are part of a bayonet catch, as will be explained below.
Figure 2 shows the male part 10 that can be inserted into the female part 1 that is shown in figure 1, which has just been described. This male or rear part 10 of the loading shell according to the present invention also forms a hollow cylinder with which a firing pin 11 is supported and guided in an axial direction, and which has an appropriately small diameter. This firing pin 11 is additionally guided at the rear by means of a guide sleeve 12 which also prevents it from falling out of the loading shell. It has a thickened section 13 in its middle area, and this is somewhat shorter than the corresponding recess 14 in the inside wall of the hollow cylinder, so that the thickened portion 13 is guided in this recess 14, al$hough the firing pin 11 can be moved through a specific range of movement in an axial direction. The firing pin 11 is of an equal length to the total rear part lo of the loading shell. At the front, this firing pin has a rounded tip 15 that is intended to strike the base of the cap of the ammunition. Externally, the rear part 16 of the male loading 3s shell part 10 is shaped so as to be identical of the shape of a conventional rifle cartridge. Thus, it has a projecting rim 15 that is created by appropriate recesses 18 and which is intended to work as a stop for the ejector on the bolt of the 2~3~8~
weapon. The front part 19 of the male loading shell part 10 has outside diameters that are the same as the associated inside diameters of the female front part l of the loading shell shown in figure 1. In particular, it has two thickened S sections ~0 that similarly extend for approximately 90 around the periphery and when rotated appropriately with respect to the front part 1 of the loading shell these correspond to the recesses 9 in this. To the right of ~he longitudinal section that is shown in figure 2 there is a front view of the male loading shell part 10, in which these two thickened areas 20 can ~e seen.
Figure 3 is a perspective view of the loading shell 21 with the ammunition 7 that is to be inserted into it, this showing the loading shell before assembly. This drawing shows the female front part 1 and the male rear part 10 of the loading shell 21. In the area l9 of the rear part 10 there are the two sections with different diameters, and the thicker areas 20 which form part of the bayonet catch. At the rear end of the rear part 10 of the loading shell 21 there is the rim 17 that is required to eject the loading shell 21 after the ammunition has been fired. Between the two parts 1, 10 of the loading shell 21 there is the ammunition 7, as it is to be inserted into the front part 1 of the loading shell 21. This consists of a cartridge case 22 and a 4~mm projectile 23 that is installed on the front end of the cartridge case 22. After the loading shell 21 has been assembled, the projectile 23 and the front edge of the cartridge case 22 extend from the drilling in the front part of the loading shell 21.
Pigure 4 shows the two parts 1, 10 of the loading shell 21 as assembled just prior to firing. The male rear part 10 of the loading shell 21 is inserted into the female front part 1 after the ammunition has been installed. To this end, the two parts l, 10 have to be rotated relative to each other so that the thickened portions 20 on the rear part 10 enter the recesses 9 in the front part 1. It is only when in this rotated position that the two parts 1, 10 can be inserted 2~28~
one into the other. After this, they are secured against coming apart by being rotated, when the thickened parts 20 on the rear part 10 rotate over the corresponding narrow sections 8 on the front part 1 in the manner of a bayonet catch when S they come to a solid stop on this. Because of a slight slope to the surfaces of the thickened parts 20 that lie against each other, or similar slope on the narrower portions 8 on the two parts 1, 10 the rotation of the parts 1, 10 relative to each other results in increasing friction, which then prevents the parts 1, 10 from rotating and being loosened. In this position, when they are inserted into each other, the front end of the male loading shell part 1 presses the ammunition 7 into ths funnel-shaped recess 5, 6 in the area of the opening of the front loading shell part 1. Of course, other means ~5 could be used to connect the two parts 1, 10. For example, it would also be possible to use a threaded connection, so that the t~o parts could be screwed together. If the loading shell that has been assembled and loaded in this manner is now inserted into the weapon, and if the trigger of the weapon is operated, the firing pin of the rifle bolt strikes the firing pin 11 inside the loading shell 21, and the tip 15 of this then, in its turn, strikes the base of the ammunition 7 and causes the charge within it to explode. The loaded and prepared loading shell 21 that is shown in figure 4 can be handled in exactly the same way as a conventional rifle cartridge. For purposes of comparison, a conventional rifle cartridge 25 is shown beneath the drawing of the loading shell 21 in its assembled state, and it can be seen that the dimensions of this cartridge 25 are identical to those of the loading shell 21 up to and including the projectile 26 that extends from the front of the loading shell. Thus, a plurality of loading shells 21 that have been prepared in this way can be loaded into the magazine of the weapon and a loading movement of the rifle bolt will expel this loading shell 21 in exactly the same way as the spent casing of a conventional rifle cartridge, even if the loading movement of the bolt has not been initiated by the pressure generated by 2~3~8~
the explosion of the ammunition that is fired, but rather by manual operation.
Up to now, only the loading shell 21 of the insert has bsen S described. Using thi~ loading shell 21, it is possible to fire ammunition of a calibre that is smaller than that for which the rifle barrel has been designed. The second element o~ the insert according to the present invention is thus an insertable barrel that can be inserted into the existing barrel of the ~irearm, thereby reducing the inside diameter or calibre of this. What is particularly difficult in respect to the insertable barrel for the Model ~0 assault rifle is the fact that the calibre of this rifle is not much greater than that of the small-calibre ammunition that is to be fired. Its ~5 calibre is 5.5 ~m, whereas the smaller-calibre ammunition that is to be fired, which is designated M20 centre fire ammunition, has a diameter of 4 mm. The wall thickness of an insertable barrel that is suitable for this purpose and which is intended ~or insertion into the conventional barrel of the Model 90 assault rifle, as is designated EP90, is thus unavoidably extremely thin.
Figure 5 is a longitudinal cross section through an insertable barrel 27 of this kind, and it also shows the associated loading shell 21 with the ammunition 7. In order to fire M20 centre fire ammunition, this insertable barrel has an inside diameter of 4 mm measured across the grooves, whereas the inside diameter measured across the lands is 4.3 mm. For this reason, the ratio of the dimension of the inner to the outer diameter of the insertable barrel 26 amounts to more than 60%, in comparison to that of the Lienhard insertable barrel, in which this ratio is clearly under 60~ for the same ammunition.
The grooves 2~ and the lands 29, which twist through 90 along the length of the barrel, are shown on the inner side of the insertable barrel. At the breech end 30, the insertable barrel 27 has a small thicker area 31 and the end edge 32 is funnel-shaped on the outside. The projectile 23 of the ammunition 7 is located at the funnel-shaped opening 5 of the 2~32~
insertable barrel 27 when the weapon is loaded, as can be seen from figure 5. The remaining outer side 33 of the insertable barrel 26, which is adjacent to the thickened section 31, is machined so as to be smooth along its whole length and thus S ha~ neither raised nor depressed sections.
It is a particular technical problem to create the required grooves 28 and lands 29 in such a thi~-walled insertable barrel 27, such that production costs can be kept within 10 acceptable limits. It is impossible to machine out the individual grooves 28 with subsequent honing and lapping of the barrel because of the high production costs discussed above. The costs that are associated with this would be unacceptable. In addition, every barrel would have to be lS subsequently straightened because the reaction forces of such processing would unavoidably twist it. In view of this problem, the pre~ent invention has created a process which treads a completely new path for such small bore diameters, in that the grooves 28 and the lands 29 are formed on the inside of the bore by means of cold forming of the barrel 27 about an appropriately-shaped core that is at least as long as the length of the barrel. Grooves 28 and lands 29 are already ~orged in rifle barrels by cold ~orming about a core.
However, the cores that are used to do this are only a few centimetres lon~, and never as long as the rifle barrel itself. During the shaping process they are held under tension on the core by a tapered extension which extends to the whole length of the barrel whilst the barrel is drawn off the core, under the hammers that are used in the shaping process. After ~orming, the barrels are straightened since they are unavoidably bent during the forming process. The smaller the barrel diameters, the more the distortion that has to be expected. In addition, straightening would be too costly for small insertable barrels. Expert opinion is that the production o~ an insertable barrel with a diameter that is clearly much smaller is impossible using the known process for cold forming, for this would unavoidably destroy the thin-wall materialO In contrast to this, the present invention creates 2~8328~
a process for producing grooves 28 and lands 29 in an insertable barrel 27 having such a small inside diameter, by means of cold forming, in that the barrel is hammered over a core that matches the negative shape of the desired inside of S the barrel and which extends to the whole length of the barrel. A core that is configured in this way, and i8 of high speed steel, will always provide the barrel with the required stability when it is being ~haped by ~he hammers, so that no distortion takes place and it thus becomes unnecessary to straighten the barrels subsequently. Three different stages in the process according to the present invention are ~hown in figures 6a to 6c, and ~igure 6d shows the finished insertable barrel. For purposes of clarity, the insertable barrels in figures 6a to 6d are all shown in one cross section. For an lS insertable barrel that is 110 mm long, for example, and which is intended for insertion into the Swiss Model 90 assault rifle, a standard tube 34 with an outside diameter of 11 mm and an inside diameter of 5 mm is used. This tube 34, which, for purposes of forming, should advantageously have a length of at least approximately 180 mm, is installed over a core 35 of high-speed steel that is approximately 150 mm long. From one end 36, the outside of this core 35 corresponds to the negative form of eight grooves 28 and eight lands 29 to a length of at least llO mm, and these make one-quarter turn along this length of 110 mm.
Figure 6a shows the situation at the beginning of the cold forming process. The standard tube 34 is installed completely over that part of the core 35 that has the grooves 28 and the lands 29. The unattached end 37 is clamped into a shaping machine, by means of which it can be withdrawn in an axial direction whilst the core 35 is ~eing rotated. The core 35, in its turn, is clamped firmly by its unattached end 38. The hammers 39 work in the same stationary location with reference to the core 35. At the start of the process, as is shown in figure 6a, the hammers 39 strike the outer side of one end of what is to be the insertable barrel. It is advantageous that the eight hammers 39 strike simultaneously, these eight 2~3~8~
hammers 39 being arranged equidistantly about the periphery sf the standard tube 34, and each strikes the outer surface in a radial direction. Every pair of hammers 39 is opposite each other, 80 that the striking forces that they generate act opposite to each other and ~hereby cancel each other out. It is advantageous that the hammers 39 have striking surfaces that are curved concavely so as to be an approximate match to the outsid~ surface of the tube. Duri~g the ha~mering process, the tube is now drawn slowly off the core 35 and at the same time a rotational movement is superimposed on this axial movement, this corresponding to the turns of the grooves 28 ~nd the lands 29 with reference to their negative shape on the coxe 35. Shortly after this, the situation is as depicted in figure 6b, in which the tube 34 has been withdrawn from 1~ approximately half the core length, so that about half of what is to be the barrel has already been formed. The forming can be seen by the taper of the tube 34 in the area 27 that has already been processed. This processing is continued until finally the tube 34 is drawn off the core 35, as is shown in figure 6c. Given the dimensions that are shown in this example, the outside diameter of the tube 34 is tapered by approximately 2 mm by the hammer blows, this resulting in a new outside diameter of approximately 9 mm. However, the outside diameter of the insertable barrel 27 must be so small that the insertable barrel 27 fits into the rifle barrel. In the case of the Model 90 assault rifle, the internal diameter is 5.5 mm measured over the lands. However, this diameter becomes somewhat larger, i.e., at the mid-point by about 3 to 6/lOOths mm, once a certain number of shots have passed through the barrel. The outside diameter of the insertable barxel 27 is now finished to this final dimension, in that it is first turned down to an outside diameter of 5.7 mm. A
thickened area, of which the edge 32 is funnel-shaped on the outside, is left in place right at the bolt end. Finally, the outside diameter is fine-machined to a dimension of 5.56 mm, after which the insertable barrel 27 is cut to the desired length, in the exampl~ shown to 110 mm, so that it ultimately appears as shown in figure 6d. The finished insertable barrel 2~28l~
is shown in longitudinal section in figure 6d. The accuracy of an insertable barrel 27 that is produced in this way is so - high that the tolerance of the inside diameter to its length of 110 ~m does not exceed l/lOOth mm in the present example.
S The hots that are fired from it are correspondingly accurate.
In order to determine the dispersal accuracy of a rifle, it is first clamped into position and 10 shots are fired from it.
The total of the points scored is a metric for the precision of the particular rifle. Rifles ~hich, when fired at a range of 300 m at an A-type target, with 10 rings, achieve a point score of 96 with 10 such ~hots are considered as first-rate firearms in knowledgeable circles, and can be offered for sale as such. Firing is conducted at 10 m using the correspondingly smaller target with 10 divisions, as used for small-calibre weapons. Tests have shown that a Model 90 assault rifle fitted with the insert according to the present invention, and firing M20 centre fire ammunition at a 70 m range can achieve a 100 shot image, which is to say a total point score of 100 when fired at a No. 10 disk (as a dispersal pattern). Becau~e of its outstanding precision, the insert according to the present invention is best suited for small-arms training. Firing as well as aiming can be practised very economically, at a level of effectiveness that has been unachievable up to now. The rifle can be converted very simply by installing the insertable barrel 27 in the breech end opening of the barrel. After firing ammunition of a smaller calibre using the insert according to the present invention the rifle can be reconverted for normal operation in that the insertable barrel 27 is pushed out of the barrel using a plastic rod which is inserted into the barrel from the muzzle end. It is, of course, understood that the insert according to the present invention can be produced for a large number of rifles or even pistols and revolvers by using the appropriate dimensions. The only condition is that the outside diameter of the associated insertable barrel be matched to the calibre of the rifle or hand-held weapon that is to be used and the loading shell correspond to a normal rifle cartridge for the particular firearm, in relation to its external 2~3~8'~
dimensions. For this reason, and in particular, it is possible to produce an insert for the Swiss Model 57 assault rifle and the Swiss carbine. Then, the insertable barrel will have an outside diameter of 7.55 mm and the exterior of the S associated two-part loading shell will correspond to the rifle cartridge 11 that is usually fired from this weapon.
: . ~ , , ,. . : .
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An insert for firearms, for firing ammunition (7) of a smaller calibre than that for which the particular firearm is constructed, this having an insertable barrel (27) and a loading shell (21) that consists of two separable parts 11, 10), characterized in that at an inside diameter of the insertable barrel (27) of less than 5mm, the ratio of the dimension of its inside to its outside diameter is more than 60%; and in that a one-piece ammunition (7) consisting of a cartridge case (22) and a projectile (23) can be inserted into the front part (1) of the loading shell (21) and a firing pin (11) is supported so as to be axially moveable in its rear part (10).
2. An insert as defined in claim 1, characterized in that the two separable parts (1, 10) of the loading shell (21) consist of a male (10) and a female (1) part which can be inserted one into the other, means (8, 9, 20) being available to secure the two parts (1, 10) in the assembled position.
3. An insert as defined in claim 2, characterized in that the female part (1) is formed internally on the side that is remote from the inserted side such that a funnel (5) is formed into which the ammunition (7) of smaller diameter that is to be loaded is pressed so as to form a positive fit by the male (10) part that is to be inserted, the projectile (23) of the ammunition (7) protruding from the funnel (5).
4. An insert as defined in one of the claims 2 or 3, characterized in that the means (8, 9, 20) to secure the two parts (1, 10) in the assembled position form a bayonet-type clasp which in the female part 11) includes a tapered inner area (8) with two opposing recesses (9) that extend axially, the male part (10) incorporating on its outside two opposing thickened areas (20) which can be slid through the recesses (9) in the female part (1) in the appropriate rotated position, after which the male (10) and the female (1) parts are rotatable relative to each other and can thereby be secured in the assembled position.
5. An insert as defined in one of the preceding claims, characterized in that the insertable barrel (27) has eight grooves (28) and eight lands (29) that twist through a quarter turn along the length of the barrel (27).
6. An insert as defined in one of the preceding claims, characterized in that the insertable barrel (27) is thicker in a small area (31) at the breech end (30) and the end edge (32) is funnel-shaped on the outside edge (32); and in that the remaining outer side (33) of the insertable barrel (27) is ground so as to be smooth along its whole length of at least 100 mm.
7. An insert as defined in one of the preceding claims, characterized in that the end area at the bolt end of the insertable barrel (27) is formed on the inside such that the ammunition (7) that is to be fired protrudes slightly into the insertable barrel (27) when loaded and the projectile (23) and the cartridge case (22) of said ammunition abut so as to form a positive fit over a small area of their outer side on the inside of the insertable barrel end area (30).
8. A process to produce an insertable barrel for an insert as defined in claim 1, characterized in that the grooves (28) and the lands (29) within the barrel (27) are produced by cold forming from the inside of the barrel in that a plurality of hammers (39) that are arranged peripherally around the periphery of the barrel act simultaneously and radially on the outside of the barrel and against a stationary core (35) that is located within the barrel (27), said core having along the whole length of the barrel the negative shape of the corresponding grooves (28) and lands (29), on a tube (34) of greater outside and inside diameter than the barrel (27) that is to be produced, while the barrel (27) is withdrawn from the core (35) under the hammers (39) while being appropriately rotated, after which the barrel (27) is turned down on the outside and subjected to finishing grinding.
9. A process as defined in claim 8, characterized in that the number of hammers (393 that are arranged around the periphery is equal to the number of grooves (28) or lands (29) on the core (35).
10. A process as defined in one of the claims 8 or 9, characterized in that a standard tube (34) of 11 mm outside diameter and 5 mm inside diameter is used as a blank, the inside diameter of this being reduced to 4 mm between the grooves (28) and to 4.3 mm between the lands (29), after which the outside diameter is turned down to 5.7 mm and ground down to a final dimension of 5.56 mm.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002083284A CA2083284A1 (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and a process for producing an insertable barrel |
| PCT/CH1991/000065 WO1992016815A1 (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and process for producing a insertable barrel |
| EP91905113A EP0530197A1 (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and process for producing a insertable barrel |
| AU74428/91A AU7442891A (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and process for producing a insertable barrel |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002083284A CA2083284A1 (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and a process for producing an insertable barrel |
| PCT/CH1991/000065 WO1992016815A1 (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and process for producing a insertable barrel |
| AU74428/91A AU7442891A (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and process for producing a insertable barrel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2083284A1 true CA2083284A1 (en) | 1992-09-20 |
Family
ID=27156080
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002083284A Abandoned CA2083284A1 (en) | 1991-03-19 | 1991-03-19 | Firearm insert for firing smaller caliber ammunition and a process for producing an insertable barrel |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0530197A1 (en) |
| AU (1) | AU7442891A (en) |
| CA (1) | CA2083284A1 (en) |
| WO (1) | WO1992016815A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140293499A1 (en) * | 2010-12-31 | 2014-10-02 | Taser International, Inc. | Electrodes For Electronic Weaponry And Methods Of Manufacture |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2103629C1 (en) * | 1997-04-08 | 1998-01-27 | Николай Дмитриевич Гурьев | Small-arms barrel |
| SE511197C2 (en) * | 1997-06-05 | 1999-08-23 | Simbal Ab | Exercise weapon system for a cantilevered recoil-free anti-tank weapon with fluted fire pipe |
| US8701326B2 (en) | 2011-12-08 | 2014-04-22 | Sturm, Ruger & Company, Inc. | Pistol barrel system and method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB190921650A (en) * | 1909-09-22 | 1910-09-22 | Federico Hartmann | Improvements in Apparatus for Adapting Small-arms for Using Miniature Ammunition. |
| CH180445A (en) * | 1935-04-08 | 1935-10-31 | Lienhard Walter | Exercise insert device for handguns. |
| BE538710A (en) * | 1954-07-05 | |||
| GB979311A (en) * | 1961-06-06 | 1965-01-01 | Ges Fertigungstechnik & Maschb | Improvements in or relating to swaging machines for the internal profiling of tubular workpieces,particularly of barrels for firearms |
| FI43547B (en) * | 1967-10-17 | 1970-12-31 | Sako Ab Oy | |
| DE1703461A1 (en) * | 1968-05-24 | 1971-12-16 | Dynamit Nobel Ag | Adapter for firearms |
-
1991
- 1991-03-19 AU AU74428/91A patent/AU7442891A/en not_active Abandoned
- 1991-03-19 WO PCT/CH1991/000065 patent/WO1992016815A1/en not_active Application Discontinuation
- 1991-03-19 CA CA002083284A patent/CA2083284A1/en not_active Abandoned
- 1991-03-19 EP EP91905113A patent/EP0530197A1/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140293499A1 (en) * | 2010-12-31 | 2014-10-02 | Taser International, Inc. | Electrodes For Electronic Weaponry And Methods Of Manufacture |
| US9173378B2 (en) * | 2010-12-31 | 2015-11-03 | Taser International, Inc. | Electrodes for electronic weaponry and methods of manufacture |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0530197A1 (en) | 1993-03-10 |
| AU7442891A (en) | 1992-10-21 |
| EP0530197A4 (en) | 1993-01-22 |
| WO1992016815A1 (en) | 1992-10-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |