US1944883A

US1944883A - Projectile propelling apparatus

Info

Publication number: US1944883A
Application number: US500040A
Authority: US
Inventors: Gerlich Hermann
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-12-24
Filing date: 1930-12-04
Publication date: 1934-01-30
Anticipated expiration: 1951-01-30

Description

Jan. 30, 1.934, GERLICH 3,944,883

PROJECTILE PROPELLING APPARATUS Filed Dec. 4, 1930 2 Sheets-Sheet '1 Jan. 30, 1934. H, GERLICH PROJECTILE PROPELLING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 4, 1930 I DNVENTOR Hermann Gerhch 2 h 62 y%w HIS ATT N EY Patented Jan. 30, 1934 Application December 4, 1930, Serial No. 500,040,

and in Germany December 24, 1929 27 Claims- (CI. 42-76) This invention relates to projectile-propelling apparatus, by which an improved ballistic performance may be effected, as regards increase of energy and speed of the projectile ejected therefrom, and other considerable advantages obtained. The invention may be practiced in connection with rifled or smooth barrels of firearms, or barrels which are partly rifled and partly smooth bore, as well as with torpedo tubes or other ballistic or projecting engines, operated by compressed air, or gases.

The invention, more particularly, relates to such apparatus in which the projectiles propelled are provided with peripheral flanges, for the purpose, among others, of increasing the area upon which the propelling gases will act. In accordance with the invention the construction of the gun or other barrel is improved so that, when a projectile of desired character is fired, the various improved efiects hereinafter described will be obtained. The invention relates to the construction of the barrel, and also to the special combination of the barrel with the particular type of projectile described, the barrel and projectile each coacting with the other, in the preferred form of device, to provide improved results due to the interaction of the two. The improved projectile per se is not claimed herein, but is the subject of a separate application.

Objects of the invention comprise the provision of improved combinations of barrels and projectiles propelled therefrom, and improved constructions of barrels, adapted to increase the ballistic performance and efl'ect of such devices, and to avoid and overcome constructional deflciencies and ballistic faults of prior constructions, the existence of which deflciencies'and defects greatly detract from the ballistic efliciency and the accuracy and precision of results.

Among features of the invention, in its pre- 40 ferred aspects, the following will here be briefly indicated. A flanged projectile is utilized, the flanges alone serving to guide and centre the projectile during its passage through the bore. The barrel of the projectile propelling device has a bore which is enlarged (with respect to the bore at the muzzle) at the start of the projectiles travel so as to give a much increased efiective cross-sectional area, (filled, as to the increased portion, by the projectiles flanges) over which the gas pressure will act. The bore tapers or decreases in cross section towards the muzzle, from some point in its length, so that the projectiles flanges will be depressed, and the material thereof pressed into suitable recesses provided in the body of the projectile, the latter emerging from the muzzle with a practically smooth form. The flanges are so arranged as properly to guide and centre the projectile, as it passes through the barrel, and also to take up the lateral pressure against the flanks of the lands in a rifled or partly rifled barrel. If rifling is used in the barrel, the tops of the lands do not contact with the body of the projectile throughout at least the greater part of the travel of the projectile through the bore. Thereby, inter alia, resistance to the passage of the projectile through the bore is greatly decreased as compared with the case where the rifling bears on the body at all times or even cuts into the body as is most frequently the case.

Preferably the first section of thebarrel, after the breech chamber, is cylindrical, or practically so, for a distance which may about equal or be rather greater than that required for the maximum gas pressure, of a propellant, to develop, so that the energy of the propelling medium will be taken up by the projectile most eiflciently.

When rifling is used the absolute heights oi. the lands, and the arrangement of the lands are preferably chosen according to special considerations, whereby increased projectile energy and so other advantages are obtained. Preferably the absolute heights of the lands, in the first part 01 the rifling, will increase in approximate correspondence with the pressure exerted on their flanks, per unit of area, by the flanges of a pro- 8 jectile passing through this first part of the bore, such increase extending up to approximately (and, if desired, beyond) the point in the projectiles travel at which the maximum gas pressure obtains. The absolute heights of the lands, in this embodiment of the invention, will, as a rule, therefore be greatest in the neighbourhood of the point of maximum pressure, and will thereafter (preferably after being maintained at maximum height for a distance) and when the pressure-ordinates of the pressure-volume-diagram are becoming appreciably shorter, decrease gradually to the required absolute height adjacent to the muzzle of the barrel. By these and other features of construction various improved results I are attained, which will hereinafter be set forth more in detail.

The cartridge, projectile and barrel are preferably mutually and accurately adapted to each other specifically in providing a constructional system, which ensures the required great increase of power, energy and speed of the projectile ballistically without unduly increasing (a) the resulting gas pressures within the bore,

- passage through the barrel;

(b) the length of the barrel, (which moreover may in some cases be shortened) (c) the weight of the fire-arm (which may in some cases be reduced) whilst yet attaining all internal and external ballistic requirements and a high degree of precision. For this purpose the effective cross sectional area of the projectile, on which the pressure of the propelling gases is to act, is increased up to a maximum, as is also the cross section of the bore of the barrel, particularly over those portions of the bore, through which the ordinates of the pressure curve will show the highest values so that whilst travelling through the maximum enlarged bore portions the main part of the propellants energy is taken up by the projectile and the latter receives its acceleration whilst still having a low sectional density. By these means a highly increased acceleration of the projectile is rendered possible within the barrel even with relatively and comparatively low gas pressures, the projectile being at the same time most effectively centered previous to starting its forward movement from its seating, and also being absolutely reliably and continually guided all along its entire travel within the barrel, and the projectile prior to its departure from the barrel having its flanges regularly depressed, with the result that a high sectional density and a ballistically favourable shape of the projectile in conjunction with an extremely high degree of axial stability is ensured for the projectile during its trajectory through atmosphere after a steady and consistently uniform departure from the muzzle of the barrel.

The projectiles preferably comprise a body having two or more axially spaced circumferential flanges, said body being preferably of a calibre not greater than, in the case of a smooth bore barrel, the muzzle diameter of the barrel from which it is to be fired, or in the case of a rifled barrel not greater than (but substantially equal to) the lands bore calibre at the muzzle. The flanges are each of a diameter equal to or slightly greater than that of the largest bore, or groove bore, diameter of the barrel and behind each flange is provided in the body of the projectile a cannelure large enough to receive wholly the flange in front thereof as the flange is depressed during the travel of the projectile through the barrel. The front and rear flanges are preferably respectively disposed at substantially equal distances in front of and to the rear of the centre of gravity of the projectile. The flanges are of large diameter as compared with the diameter of the body of the projectile and serve, firstly, for reliably and correctly centering the projectile previous to being fired and also during its entire secondly, for effectively sealing the bore against the propelling gases during the projectiles movement through it, and thirdly, for reliably and steadily guiding the projectile all along its entire course within the barrel and at the same time preventing all axial tilting movements and radial displacements of the axis of the projectile and projectile nutations during the projectiles movement within the bore of the barrel whilst taking up at the same time the effective and specific pressure on the flanks of the lands in connection with rifled barrels. The projectile thus maintains a perfect equilibrium within the bore from its start to its departure from the muzzle and its centre of gravity of the projectile is thus steadily, continu- This is of extreme importance as regards the steady and concentric progressive squeezing back and down of the flanges. In the case of fully rifled arms the front of the foremost flange of the projectile is congruent with the shape and inclination of the lead from the breech chamber into the rifled part of the bore (i. c. with the rear ends of the lands), against which it bears. This applies both to fire-arms and the like in which a single complete cartridge is used, in which the projectile is tightly inserted in the cartridge neck, and also to fire arms in connection with which projectile and cartouches are kept separate.

The process of displacing the flange-material takes place locally on very short axial stretches on the circumference of the projectile without any deformation of the projectile which would have an unfavourable effect by shifting material radially and eccentrically thus incorrectly displacing the centre of gravity, which should be avoided. The rear edge of the rearmost cannelure behind the rearmost flange of the projectile should axially be placed slightly away from the rearmost cross section of the cylindrical portion of the projectile body proper (whether having a boat tail or cylindrical rear end.

In order that the invenion may be more clearly understood attention is hereby directed to the annexed drawings forming part of this application and illustrating diagrammatically by way of example certain embodiments of the invention.

Figs. 1 to 3 of the annexed drawings show diagrammatically boat-tailed rifle bullets of the kind referred to.

Fig. 4 shows a complete rifle cartridge with the bullet tightly held in the neck of the cartridge case.

Figs. 5 to 7 show diagrammatically ordnance projectile in which the projectile flange-rings may be slotted as in Fig. '7 in the sense of the twist or the angle of the rifling for the lands of the rifled barrel.

Fig. 8 shows in sectional elevation the chamber and the lead into the rifled portion of a barrel according to this invention whereas Fig. 9 shows an elevation of the bore of the barrel, seen in the direction of the arrow.

Figs. 10 and 11 illustrate diagrammatically in part longitudinal section and end elevation respectively a further and slightly modified form of barrel.

Figs. 12 to 15 show diagrammatically and exaggeratedly further forms of barrels according to this invention in longitudinal sectional elevation.

In the drawings s indicates the centre of gravity of the projectile and a and b the rear and front projectile flanges respectively, between which is axially practically centred the centre of gravity of the projectile. The diameter of the cylindrical portions of the projectile body, may, where required, as for instance for small arm projectile be slightly in excess of the lands calibre of the barrel at the muzzle.

For smooth bore arms and the like, as for example in connection with smooth bore mine throwing and similar guns and for torpedo lancing tubes the projectiles may be provided with flanges of lead leather or similar plastic or readby deformable materials. In the case of rifled barrels the flanges may take up alone the entire specific pressures on the flanks of the lands thus efiecting the rotation of the projectile. When firing or propelling such projectiles from barrels with a progressive twist of the rifling and if for instance but two flanges are provided, these flanges may, if required, be preferably placed at a very short axial distance from each other and axially on opposite sides of the centre of gravity of the projectile.

In order to obtain -the required increase of the ballistic effect with projectiles such as described the barrels according to this invention and from which the projectiles are fired are constructed and bored in the following manner. In the case of rifled arms the lands, which are, as far as possible, reduced in number, are made as narrow as possible and are preferably not executed with sharp upper edges and may be also rounded off with a slight radius at their bases. The land calibre may be widened over a certain portion of the projectiles travel within the bore preferably along the first portion thereof. The lands caliber may thus and over anydesired length of the bore or of the projectiles travel be cylindrical and of constant diameter, but appreciably widened in relation to the diameter of the body proper of the projectile, and then starting from a certain and suitable point of the bore gradually tapering down towards the muzzle end of the barrel conically, parabolically or according to any suitably plotted curve, or may be tapering down and narrowing in this way right from the very start of the rifled portion of the barrel, i. e. from the breech chamber end onwards. If required, the land calibre may be widened to a maximum extent but tapering down towards the muzzle over the first portion and any 'desired'length of the projectiles travel and then from a certain and suitable point onwards be kept less wide with a constant diameter, although with a diameter appreciably larger than that of the body proper of the bullet, after which the lands bore again tapers down to the normal calibre adjacent the muzzle as is, of course essential. The lands may advantageously, tapered towards the lead into the rifled portion of the barrel, taper wedge-like laterally as well as on their top parts whereby they will cut more easily and more gradually into the above mentioned projectile flanges without a too forcible, sudden and immediate pressing back and rearward displacement of the flange material. The first taper or inclined top surfaces of the lands will subtend a greater angle at the axis of the bore than the main tapered portion of the lands bore as it is of course shorter axially than the latter. The gradual narrowing of the lands calibre and the gradual reduction of the diameter of the groove bore will in the front portion of the barrel and near the muzzle effect the pressing back and levelling down, of the projectile flange material, into the cannelures behind the flanges, which become filled up level practically with the surface-contour of the body proper of the projectile.

ing gas pressures without risking any squeezing away or shearing off of the projectile flanges.

An appreciably widened cylindrical and also a widened conical or parabolic lands bore over' a more or less lengthy portion of the projectiles travel within the barrel and also a lands bore with lands rather low and of wider calibre at the chamber end and gradually decreasing in calibre, result in increase of effective cross sectional area and in a reduction of the resistance which is offered to the projectile when being pressed into the rifled portion of the bore, and also in a reduction of the gas pressure due to reduction of resistance; also in a reduced and more gradual and more uniform and still more controllable deformation of the projectile flanges result from these improvements especially over those sections of the bore over which maximum gas pressures and highest accelerations prevail; also there is less wear of the bore and especially of the lands over the said sections of the bore as well as appreciably less heating of the lands owing to their surfaces exposed to the action of the flame of the propelling charge being greatly reduced in area and owing to the considerably facilitated transmission of heat under these more favourable conditions from the top parts of the lands of the rifling, (which are the most ex posed to the flame of the burning charge and the propelling hot gases and which therefore are taking up heat most intensively), to the mass of the barrel itself. This is indeed a feature, which is of special importance in practice with regard to the life of the barrels in question.

The initial height f the lands may be reduced over the portion of the barrel having the largest groove diameter to 50% or less which that height of the lands would have at this part of the bore if the lands calibre was constant throughout the barrel and the same as the minimum lands calibre. The maximum cylindrically enlarged land-calibre, or, if required, also a gradual reduction of the widened land caibre, could practically be extended over that length of the projectiles travel over which the groove calibre is also widened substantially cylindrically to a maximum with a constant diameter etc. The ratio of the widening of the land calibre and the absolute height of the lands along this part of the projectiles travel may incidentally be regu'ated according to the curve of the specific pressure with which the projecting flanges are bearing on the flanks of the lands, which preferably may also be the .case in the second and further portion of the bore, over which the groove calibre is gradually narrowing according to a suitable taper.

The groove diameter of a rifled barrel is enlarged to the best possible extent from the rearmost portion of the bore proper, i. eubreech chamber end of the barrel. This very marked widening of the groove bore is to be effected according to conditions prevailing specifically and should be made as large as possible. The grooves should at the same time be made as broad as possibe with a corresponding narrowing of the lands. in order to obtain the greatest possible increase of effective bore cross section. Over the first portion of the bore which is dimensioned according to specific conditions prevailing and which should be made as long as possible, the groove bore should preferably be kept practical- 1y constant with a maximum diameter (as compared with the groove or lands calibre at the muzzle of the barrel) in such a. manner that along this first portion of the bore the groove bore is practically cylindrical, and that starting tive projectile cross sectional area along this portion of the projectiles travel, which is decisive for the absolute amount of work or energy taken up by the projectile, so that the ballistic effect and the dynamical eificiency of this method becomes very great under these'circumstances.

The first portion of the bore (-in armed bore the lands bore as well as the groove bore) enlarged to a maximum extent in the manner described, then merges gradually and smoothly into a second bore portion, (the bore of which is narrowing conically or parabolically or tapering down according to some other specifically suitable curve and the proportional length of which portion is determined by the specific conditions and requirements of each case. In the last portion of the projectfles travel near the muzzle of the barrel, over which the ordinates of the gas pressure-and accelerationcurve only show comparatively low values, the groove bore may be reduced to a normal and constant size and the lands bore at the same time may be of normal and constant calibre. This last and cylindrical portion of the bore of normal and nominal size may shoe the usually standard and con stant dimensional diiiercnces and relations between groove diameter, lands diameter and bullet diameter-as heretofore usual in rifled arms. The length of this last normaly rifled and bored portion of the bore near the muzzle may be determined ad libitum and according to specific requirements.

A portion of the projectiles travel corresponding approximately to one quarter or so of the length of the twist of the rifling or to about double the projectile length or about five to six times the axial bearing length of the projectile may as a rule be taken as amply sufiicient length for this last normally bored portion of the bore. As a rule this portion may be cut down in length to about 5% of the total length of the projectile's travel Within the barrel.

The projectile consequently and whilst travelling along the entire axial length of the bore will be gradually pressed into a form and shape exceedingly favourable and effective ballistically- The complete disappearance of the projecting flanges and the simultaneous levelling up of the cannelures is finally effected Whilst the projectile is passing through the last portion of the bore. A projectile of standard weight f or a given calibre then leaves the muzzle of the arm with a stand- ,ard sectional density, whereas its initial speed,

i. e. its muzzle velocity, is most considerably and decisively increased as compared with the muzzle velocity of a normal projectile fired from a usual barrel by the very highly increased absorption of energy without any corresponding increase of the accelerating gas pressures or any undue absolute increases of pressure whatsoever. Even with increased projectile weight and increased sectional density the muzzlevelocity of the projectile fired from a barrel according to this'invention will be the same as or even ,higher than .is the case with a projectile of standard or of even considerably lighter weight fired from a corresponding barrel of standard construction, this being the case even when using practically same and identical gas pressures in both types of barrel. Such a projectile warrants at the same time a high degree of axial stability and steadiness of flight under these conditions. A most excellent value of form and an extremely high ballistic coeflicient may be realized witha projectile fired with such an extremely increased initial speed, the trajectory of which projectile becomes more rasant and exceedingly flat owing to its highly increased velocity and extreme ranging power (enormously reduced. times of flight). Such a projectile, whilst possessing excellent precision and accuracy, renders possible an extreme and actually decisive increase of its striking energies, i. e. also its striking velocities, and threeby an enormous increase of its destructive and piercing efiects. In connection with these increased ballistics due attention should be paid to the importance of reaching specifically critical speed-limits and also to the fact, that at these higher bullet-speeds air resistance is not increasing at the same high rate as is the case within lower bullet speed-limits.

Fig. 8 shows the construction of the barrel with a cylindrical groove bore of maximum diameter over the first portion of the bore, the lands calibre in this first portion of the bore being also considerably widened narrowing down gradually along the bore in the manner described to the nominal. or minimum lands calibre, which same as the groove bore which is also narrowed down towards the muzzleremains constant in the very last portion of the bore near the muzzle. The lands calibre may be bored as shown in Fig. 8 so that it is narrowing immediately from the abrupt ends of the lands with any suitable taper to the lands calibre at the muzzle or, as shown in Figs. 10 and 11 which illustrate a construction of the barrel with an appreciably widened cylindrical groove bore of constant maximum diameter over the first portion of the bore, the lands calibre may be appreciably widened over this first portion of the bore with a constant maximum lands bore diameter. In this instance therefore--the bores of the grooves g and lands I over this first portion of the bore are cylindrical and axially parallel. This is the modus of construction, which as a rule guarantees the maximum increase of ballistic effect.

Fig. 12 shows diagrammatically in longitudinal section a rifled barrel having a groove bore with an enlarged cylindrical section 11 at the breech chamber end of the bore, a cylindrical section 7' at the muzzle end 'of the bore, these sections be ing joined together by a tapered section It in creasing in diameter'towards the end where it meets the cylindrical section. The lands bore is constant over a portion Z extending a distance from the muzzle and then increases in calibre over a part 111. gradually at a difierent rate of taper to the park k of the groove bore and relative to the bore axis, then the lands bore has an enlarged cylindrical part 12 after which it is again gradually enlarged towards the breech chamber over a part 0 at a difierent rate of taper relative to the bore axis than the tapered portion k.

Fig. 13 shows a similar groove bore to Fig. 12 but the lands bore in this case has not the part 0 shown in Fig. 12, the lands bore remaining of constant calibre right up to the breech chamber.

Fig. 14 shows a partially smooth and partially rifled barrel having a groove bore as in Figs. 12 and 13 but here the lands bore portion m terminates between the ends of the bore in a part 1) somewhat similar to the part 0 in Fig. 12.

Again Fig. 15 shows a similar groove bore to Figs. 12, 13 and 14, but here the lands bore increases in calibre in a straight taper q right from the inner end of its muzzle section I to the breech chamber end of the bore.

The guiding of the projectile is effected only and exclusively by the projecting flanges a and b, that is to say only by their bearing on the groove surfaces 9 and on the lands f, as far as these are cutting into the projecting flanges, without involving the necessity of the projectile-body proper to come into bearing contact even only with the topparts of the lands and without being required to be guided thereby. The reliable and efiicient guiding of the projectile required for reliable and consistent precision is effected by a couple or a plurality of narrow annular areas separated from each other by some distance instead of following the usual style-especially in connection with metal patched rifle bullets-of guiding the bullet on a single longer and considerably larger bearing surface. This, and also the fact that the lands (which vary in absolute height as previously stated approximately according to the lateral pressure curve) have higher flanks than usual and participate to a much greater extent in the guiding of the projectile-are fundamental and principal differences between the improved and usual method of guiding the projectile and are very important factors in practice.

By this method of guiding and supporting the projectile drawbacks of guiding on an axially longer and greater coherent single surface of the projectile are most effectively eliminated and indeed so without any new disadvantages resulting. Moreover using very high projectile velocities and an appreciably widened land calibre ensures that practically all metallic fouling of the bore by the flange-materials of the projectiles is effectively avoided or reduced.

As an example of the enormous advantages and decisive increases in ballistic performance and effects which may be obtained by the described constructions a Cal. 7 mm. rifle may for instance be taken. This rifle fires the well known 7 mm. Mauser military cartridge, which in a barrel 74 cms. or 29%" long imparts to its 10 grammes (154 grs.) Spitzer bullet a muzzle velocity of about 860 m./sec. or just about 2,830 ft./sec. with a powder charge of 3.25 grammes. Corresponding to a bullet diameter of about 7.2 mm. the effective cross sectional area is in this instance practically 40 mm With a flange projecting around the circumference of the body of the bullet for instance 1 mm. the diameter becomes increased to 9.2 mm. corresponding to cross sectional area of 66 mmfi. This, as compared with the 7.2 mm. bullet, represents an increase of cross sectional area of 26mm. or By making the lands narrower than usual and as shallow as possible only a minimum of this increased effective area is, in the early stages of the projectiles movement, lost by flange displacement by the lands.

Especially in view of the fact that along the first portion of the bore, which may be extended over a very considerable length of the entire bore, the effective cross sectional areas of the bore and the bullet may be increased almost ad libitum to an effective maximum, as described, and since all along this first portion of the bore and the bullets travel the absolute and mean effective gas pressures are by far the greatest and moreover, if the propelling charge or the developed gas-volume is increased approximately in correspondence with and in relation to the increase of the cross sectional area or volume, a very great and most decisive increase of bullet energybe it with regard to the weight or the velocity factor or with regard to both-may be actually realized over the same length of the projectiles travel or with the same lengthor even shorter lengthof barrel without abnormally and unduly increasing the pressure acting upon the projectile. This will be especially so if a modern propellant of sufficient cubic density is chosen which burns specifically more quickly than usual propellants and which will be especially eflicient if specifically tuned up in correspondence with the greatly increased effective cross sectional areas and the higher rate of increasing the volume behind the projectile owing to a very high increase of bullet acceleration. This enormous increase of bullet energy thus actually and practically obtained may be suitably utilized as required in every case, and whilst keeping the pressures within usual and normal limits, either by proportionately increasing the absolute weight of the projectile in connection with the same muzzle velocity, or especially by most considerably and decisively increasing the muzzle velocity of a projectile of standard weight and of standard ultimate sectional density. This very great increase of energy of theprojectile or of its ballistic power and performance may thus and according to the method described be practically and actually utilized within very wide limits and indeed could be realized with a cartridge and in a weapon of specifically normal dimensions and standard weight; or even with such a cartridge but with a shorter barrel by employing a specifically sharper burning and sufiiciently dense propellant.

This invention may of course be applied-and especially if certain constructional details are correspondingly alteredto smooth bore arms, the bore of which is executed either cylindrically at the start with an enlarged inner diameter or tapered and narrowing down according to a suitable, curve right away from the very chamber. The smooth bores may be bored in a manner analogous either to the groove bores or the lands bores of the rifled barrels described, the bores of which may be executed with diameters narrowing down towards the muzzle according to any desired and suitably plotted specific curve-and indeed so either with regard to the entire length of the bore or only with regard to portions thereof and with regard to the groove bore as well as to the lands bore. Besides barrels may be executed ad libitum with any desired combination of the described types and styles of boring for certain specific purposes and under certain conditions, for example barrels may be made, which are rifled over cerameter at this part, the groove bore being, for the purpose of explaining its form, imagined in all cases without the lands whether the bore is or is not rifled. By the term "taper used in the claims is meant either a straight taper or any suitable curved taper.

1. Projectile propelling apparatus comprising a barrel having a breech chamber and a bore consisting of three sections, namely, a muzzle section remote from the breech chamber and of substantially normal dimensions for the projectiles for which the barrel is designed, a substantially cylindrical section adjacent to and following the breech chamber, such section being of enlarged diameter as compared with the substantially normal diameter of the muzzle section, and such cylindrical section extending along the barrel for a substantial length sufflcient to enable a projectile passing through this section to be subjected whilst therein to the action of the propelling gases during the time they are at their higher pressures, and a section connecting such substantially cylindrical section to the muzzle section and decreasing (from the cylindrical section end of the barrel to the muzzle section end thereof) gradually from the diameter of the said enlarged substantially cylindrical section to the diameter of the muzzle section said connecting section extending over a relatively long portion of the bore.

2. Projectile propelling apparatus comprising a barrel having a breech chamber, a groove bore consisting of a muzzle section having a cross sectional area substantially normal for an ordinary unfianged projectile having the calibre of the body of a flanged projectile to be used with the said propelling apparatus, a substantially cylindrical section at the breech chamber end of the barrel, such section being of a cross sectional area greater than the muzzle section and in excess of that of the body of the said projectile and following the breech chamber, and a section connecting said substantially cylindrical section with the muzzle section, the cross sectional area of such connecting section decreasing (towards the muzzle section) from that of the cylindrical section of the barrel to that of the muzzle section of the barrel, said connecting section being relatively long as compared with the said enlarged cylindrical section, said barrel having rifling and the lands bore being of a diameter substantially normal for the said projectile at the mouth of the muzzle of the barrel and being increased in diameter from such mouth towards the breech end of the latter.

3. Projectile propelling apparatus comprising a breech chamber, and a rifled barrel comprising three sections, namely, a muzzle section remote from the breech chamber and the calibre of the lands bore of which is substantially equal to the diameter of the body of the projectile for which the barrel is designed whilst the absolute heights of the lands in this section are substantially those which would be normal for an ordinary constant bore diameter barrel having a cylindrical lands bore of the said calibre, a substantially cylindrical section adjacent and following the breech chamber, the groove bore of such section being of enlarged diameter as compared with the normal diameter of the muzzle section, and such cylindrical section extending along the barrel for a length sufficient to enable a projectile passing through this section to be subjected to the action of the propelling gases from the time they commence to act to and during the time when the gases are at their higher pressures, and a section connecting such 'substantially cylindrical section to the muzzle section and the groove bore of which decreases radually from the diameter of the said substantially cylindrical section to the diameter of the muzzle section, and the lands bore of the barrel being increased in calibre towards the breech chamber end of the barrel.

4. Projectile propelling apparatus comprising a breech chamber and a rifled barrel having a groove bore formed in three sections, a muzzle section having a cylindrical groove bore normal for the calibre of projectile for which the barrel is designed, a substantially cylindrical section at the breech chamber end of the barrel, and the diameter of which is greater than the diameter of the groove bore of the muzzle section, said cylindrical section being of a length suflicient to enable a projectile passing therethrough to be'subject whilst therein to the action of the propelling gases during the time they are'at their higher pressures, and a section. connecting said substantially cylindrical section with the muzzle section, the diameter of which section decreases from the diameter of thecylindrical section of the barrel to the diameter of the muzzle section, and the lands bore being in the muzzle section of normal diameter for the said projectile, but gradually increasing in diameter from the muzzle section of the barrel towards the breech end of the barrel and the lands ending and merging into the groove bore between the muzzle section and the breech end of the said cylindrical section.

5. Projectile propelling apparatus comprising a breech chamber and a barrel having a groove bore including a muzzle section of a cross sectional area substantially normal for the projectile which the barrel is designed to project, a cylindrical section adjacent to and following the breech chamber, said cylindrical section being of such a length that during the movement of the projectile therethrough the latter is subjected to the pressure of the propelling gases from the commencement of their action until they attain their maximum pressure, and such cylindrical section also being not less than 20% greater in cross sectional area than the body of the projectile, and an intermediate section connecting said cylindrical and muzzle sections and decreasing in cross sectional area from the former section to the latter section, lands extending along the bore of said barrel, and the lands bore increasing in calibre from normal calibre at the muzzle section end towards the breech chamber end of the barrel until the lands finally end and merge into the'groove bore between the breech chamber end of the said cylindrical section and the muzzle section, and said lands having their tops and sides bevelled at the ends nearest the breech chamber.

6. Projectile propelling apparatus comprising a rifled barrel having, in addition to the breech chamber, a groove bore which is, at the mouth of the barrel, of a diameter substantially normal for the projectile for which the barrelis designed, said groove bore being of enlarged diameter at the breech chamber end thereof and being reduced, between its ends, from the said enlarged diameter to the said normal diameter, and the lands bore being also enlarged towards the breech chamber end of the barrel and the largest calibre of the lands bore being greater than the calibre of the body proper of said pro- 1 jectile, and the lands merging into .said groove 1 barrel, of a calibre substantially equal 'to that chamber, a rifled bore having a muzzle section' of ,the body of the projectile for which the barre l is designed, the groove bore diameter at the muzzle being substantially normal for such a lands calibre, and said groove bore being of enlarged diameter at the breech chamber end thereof and being reduced, between its ends, from the said enlarged diameter to the saidnormal diameter, and the lands bore being also gradually enlarged in calibre from a point nearer the mouth of the barrel than the breech chamber end thereof and in a direction towards the breech chamberend of the barrel, such lands calibre enlargement being at a rate of taper (relative to the axis of thebore) difierent tothatat which the groove bore increases.

8. Projectile propelling apparatus comprising a breech chamber and a rifled barrel having a.

bore which is, at the muzzle of the barrel, of a diameter substantially equal to that of the body of the flanged projectile for which the barrel is designed, the groove bore being of enlarged diameter at the breech chamber end thereof and being tapered, between its ends, from the said enlarged diameter to the said muzzle diameter, said tapered portion of the groove bore extending over a relatively long portion of the barrel, and the lands bore being also enlarged towards the breech chamber end of the barrel, and the largest calibre of the lands bore being greater than the calibre of the body proper of said projectile, and the lands merging into said groove bore between the muzzle and enlarged ends thereof.

9. Projectile propelling apparatus comprising a barrel provided with, in addition to a breech the lands bore calibre at the mouth of which is substantially equal to the calibre of the body of a flanged projectile for which the barrel is designed and the groove bore diameter of which is substantially constant throughout the section and substantially normal for said lands bore calibre, and a further section between the breech chamber and the muzzle section and the groove bore diameter of which is enlarged gradually in diameter, from where it joins the groove bore of the muzzle section, in a direction towards the breech chamber, the lands bore of the barrel also being gradually enlarged in calibre in a direction towards the breech chamber end of the barrel and to a point at which the lands are of an absolute height which is greater than the height of the lands at the mouth of the rifled muzzle part of the barrel, and the rear part of the lands bore (1. e. the part between the said point and the lands ends nearest the breech chamber) being again gradually and further enlarged in calibre with a diflerent angle of taper towards the breech chamber.

10. Projectile propelling apparatus comprising a barrel having a breech chamber and a rifled bore, in which gas pressure is adapted to increase to a maximum during the first portion of a projectiles travel therethrough, and to thereafter decrease, the lands bore thereof being, at the muzzle end thereof substantially equal in calibre to the calibre of the body of the projectile for which the barrel is designed, and the groove bore thereof being, at the muzzle end thereof, substantially normal for such a lands bore, said lands and groove bores being, adjacent to the breechchamber end of the bore, of enlarged dimensions as compared with their.muz-

zle dimensions, the lands increasing in heightg from the beginning of the rifling, in approximate correspondence with the lateral pressure per unit of bearing area exerted on their flanks.

.by' a projectile passing'through the barrel, up to approximately the point of' the projectiles travel at which the maximum gas pressure obtains, at which point the heights of the lands are greater than at the muzzle, .the heights of the lands subsequently decreasing, in the direction of the muzzle.

11. Apparatus for propelling a flanged projectile and comprising a'barrel having a breech provided with a further section between the breech'chamber and the muzzle section and the groove bore diameter of which is enlarged at the breech chamber end thereof and which section gradually decreases in diameter to the point Where it joins the groove bore of said muzzle section, the lands bore of the barrel also being enlarged in calibre in a direction from the muzzle end portions'forming bearing surfaces adapted to be engaged by a flange of said projectile, and the said bore being at its largest part of a cross sectional area at least 20% larger than that of the said muzzle section at its mouth.

12. Projectile propelling apparatus comprising a breech chamber and a rifled barrel the lands bore of which is at the mouth of the barrel substantially equal to the calibre of the body of the projectile for which the barrel is designed, such barrel having,a groove bore in three sections, namely, a muzzle section remote from the breech chamber and of a diameter substantially normal for said lands bore calibre, a substantially cylindrical section adjacent to and following the breech chamber, such section being of enlarged diameteras compared with the diameter of said muzzle section, and such substantially cylindrical section being of a length sufficient to enable a projectile passing therethrough and whilst therein to be subjected to the action of the propelling gases from the commencement of their action to and during the time they are exercising their higher pressures, and a single section connecting said substantially cylindrical section to the muzzle section and decreasing, in a direction from thebreech chamber end thereof to the muzzle end thereof, from the diameter of said enlarged cylindrical section to the diameter of the muzzle section groove bore, and the lands bore increasing in calibre, in a direction from the muzzle section towards the breech chamber, to a point from which the lands are ramped (ie. the lands bore is again gradually increased in calibre with a different angle of taper in a direction towards the breech chamber end of the bore).

13. Projectile propelling apparatus comprising 4 a barrel having riding and also having in addition to a breech chamber, a muzzle section the lands bore at the mouth of which is of a calibre substantially equal to that of the body of the pro-' jectile for which the barrel is designed and the groove bore diameter of such muzzle section being substantially constant and normal for said lands bore, and a further section between the breech chamber and the muzzle section thegroove bore diameter of which is enlarged at the breech chamber end thereof and gradually decreases to the point where this section joins the groove bore of the muzzle section, the lands bore being also enlarged in calibre in a direction towards the breech chamber end of the barrel at a slower rate of taper relative to the axis of the barrel than that at which the groove bore diameter is increased, the said enlargement of the lands bore continuing We point between the ends of the lands at which the absolute height of the lands is greater than the height .of the lands at the muzzle, the lands calibre subsequently being again gradually increased (the absolute height of the lands being consequently decreased) towards the origin of the lands where the latter-merge into the groove bore between the ends of the tapered section thereof.

14. Apparatus for propelling flanged projectiles comprising a rifled barrel having a groove bore, including in addition to the breech chamber, three sections, namely, .a substantially cylindrical section adjacent and following the breech chamber and having a cross sectional area at least 20% greater than that of the projectile body for which the barrel is designed and substantially corresponding in groove bore diameter with the diameter of peripheral flanges on the projectile, such cylindrical section being of a length sufficient to enable the propelling gases to act on the projectile (including the flanges) while it is therein, from the commencement of their action until they attain their maximum pressure, a muzzle section the groove and lands bores of which are cylindrical and in which the lands bore calibre is substantially equal to the calibre of the said projectile body, and a single intermediate section connecting said cylindrical and muzzle sections together and the groove bore of which decreases gradually in diameter from the enlarged cylindrical section to the muzzle section, the lands bore calibre gradually, and at a slower rate of taper relative to the barrel axis than the said groove bore, increasing through the said intermediate section towards the breech chamber end to a point at which the lands are of an absolute height which is greater than the absolute height of the lands at the muzzle section of the barrel, and the calibre of the lands bore then, from a point nearer to the breech chamber than the first named point and within the cylindrical section of the groove bore, being again gradually increased towards the breech chamber, and the lands having their sides bevelle off towards their breech chamber ends. 1 i

15. Projectile propelling apparatus comprising a barrel having a breech chamber and in addition to the latter a bore consisting of three (only) end to end coaxial sections, namely, a cylindrical muzzle section remote from the breech chamber and of substantially normal dimensions for the standard calibre of the projectile body proper for 1,944,aes

which the barrel is designed, a cylindrical section adjacent to and following the breech chamber, such section being of enlarged diameter as compared with the substantially normal diameter of the muzzle section, and an intermediate section connecting such cylindrical section to'the' muzzle section and decreasing continuously in its diameter according to any suitable continuous taper (from the end of the enlarged cylindrical section of the bore to the beginning of the practically normal muzzle section thereof) from the diameter of the said enlarged cylindrical section to the diameter of the muzzle section and such intermediate section extending over a relatively large' portion of the bore as compared with said enlarged cylindricalsection and decreasing gradually and steadily in its diameter along said taper and without abrupt short and relatively steep contractions or conical transition chokes.

16. Projectile propelling apparatus comprising a barrel having a breech chamber, a groove bore consisting of a muzzle section having a cross sectional area substantially normal for a projectile having the calibre of the body of the projectile to be used with the said propelling apparatus, a substantially cylindrical section at the breech chamber end of the barrel, such section being of a cross sectional area greater than the muzzle section and in excess of that of the body of the said projectile and following the breech chamber, and a section connecting said substantially cylindrical section with the muzzle section, the cross sectional area of such connecting section decreasing from that at the forward end of the cylindrical section of the barrel to that of the inner end of the muzzle section of the barrel, said barrel having rifling and the lands bore being at the muzzle section of the barrel of a calibre substantially normal for the said projectile and being increased in calibre towards the breech end of the barrel, and the absolute heights of the lands being at a part of the lands between their ends greater than in the muzzle section of the barrel.

1'7. Projectile propelling apparatus comprising a rifled barrel having in addition to a breech chamber and between the latter and its forward extremity a rifled bore, the lands bore of which is, at the muzzle of the barrel, of a calibre substantially equal to that of the body of the projectile for which the barrel is designed whilst the groove bore diameter is at this part substantially normal for such a lands calibre, said groove and lands bores being with respect'to the muzzle end of the bore enlarged in diameter and calibre respectively at different rates of taper relative to the axis of the barrel and in a direction from the I muzzle towards the breech chamber, the lands being, nearer their breech chamber ends than their muzzle ends of a maximum absolute height which is greater than the absolute height of the lands at the muzzle of the barrel, the said lands varying in absolute height approximately in proportion to the curve of lateral pressure per unit of bearing area which would be exerted by the flanges of a flanged projectile on the flanks of the lands.

18. Projectile propelling apparatus comprising a rifled barrel having in addition to the breech chamber and between the latter and its muzzle, a rifled bore the lands bore of which is at the mouth of the barrel of a calibre substantially equal to 7 in diameter throughout a part of its length and terminating in a cylindrical section in front of the breech chamber and of a larger diameter than the groove bore at the mouth of the barrel, and said lands calibre also increasing towards the. breech chamber end of the barrel gradually over the greater part of its length and later and nearer the breech chamber end of the barrel increasing in calibre ata greater rate of taper relative to the axis of the bore than before, such increases of the lands bore calibre and the corresponding heights of the lands being regulated in approximate accordance with the curve of lateral pressure whichwould be exerted on the flanks of the lands by the flanged projectile.

19. A projectile propelling apparatus comprising a barrel having in addition to a breech chamber, a bore extending from the breech chamber to the forward extremity of the barrel, such bore having rifling and the groove bore having three sections, namely, a cylindrical section at the for: ward end of the bore and the lands calibre of which is substantially equal to the calibre of the body of the projectile for which the barrel is designed and the groove bore diameter of which is normal for such a lands bore, a cylindrical section next to and in front of the breech chamber, such cylindrical bore section being of enlarged diameter as compared with the groove bore of the first named cylindrical muzzle section, and an intermediatesection longer than either of such cylindrical sections and increasing gradually in diameter from the diameter of the cylindrical section at the forward end of the barrel to the diameter of the enlarged cylindrical section at the breech chamber end of the barrel, each of the three said sections merging smoothly into the adjacent section, the calibre of the lands bore being enlarged in a direction towards the breech chamber end of the barrel, and the lands increasing in absolute height from ends nearest the breech chamber at first at a relatively quick rate of taper with relation to the axis of the bore and approximately proportionally to the increase in the pressure ordinates of the gas pressure-volume curve for the barrel, the lands then for a stretch being constant in absolute height, and then gradually decreasing in absolute height until a normal height is reached.

20. Projectile propelling apparatus comprising a rifled barrel having in addition to a breech chamber and between the latter and the mouth of the barrel a rifled bore the groove bore of which is formed in three sections, a cylindrical muzzle section, a cylindrical section next to and in front of said breech chamber and of a greater diameter than said muzzle section, and an intermediate section extending from the muzzle section to the enlarged cylindrical section and increasing from the diameter of the former section to that of the latter, the lands bore calibre also being increased towards the breech chamber end of the barrel at a different rate of taper (relative to the axis of the barrel) to said intermediate section of the groove bore, and to a point from which the lands bore calibre remains for a distance constant, the lands here being of greater absolute height than are the lands at the mouth of the barrel, after which the lands bore calibre is again gradually increased, the rate of taper of this last named portion of the lands bore being such that, from their breech chamber ends to the nearest end of said constant portion of the lands bore, said lands increase in absolute height approximately in proportion to the increasing latmuzzle section of the groove bore being of a di ameter normal for the lands bore calibre of this section and which calibre is substantially equal to that of the body of the projectile for which the barrel is designed.

21. Projectile propelling apparatus comprising 1 a barrel having, in addition to the breech chamber, a rifled bore, the groove bore of which is formed in three parts, namely, a cylindrical muzzle part of a diameter greater than the diameter of the body of the projectile for which the barrel is designed, a portion next to, and in front of, the breech chamber end of a greater diameter than the cylindrical muzzle part, and a third part joining the other two parts of the groove bore and increasing in diameter from the diameter of the muzzle part to the diameter of the part next to and in front of the breech chamber, the lands bore being, at the mouth of the barrel, of a calibre substantially equal to the diameter of the body of the projectile and also being, between the ends of the barrel, increased in diameter for a part of the length of the lands and in a direction towards the breech chamber, such lands bore then remaining of constant diameter for a further part of its length and the absolute heights of such lands being over a portion of their lengths greater than the absolute heights of the lands in the muzzle part of the barrel.

22. Projectile propelling apparatus comprising a barrel having a breech chamber and being partly rifled, the lands bore being at the muzzle part of the barrel of a diameter substantially equal to that of the body of the projectile for which the barrel is designed whilst the groove bore is at this point of a diameter normal for such a lands bore, said groove and lands bore being substantially constant in diameter and calibre respectively for a distance from the mouth of the barrel and then gradually increasing in diameter towards the breech chamber end of the barrel, but the lands bore increasing in diameter at a different angle to the axis of the barrel than said groove bore, and the lands entering into the groove bore between the ends of the portion thereof of increasing diameter, the bore being smooth and unrifled from the points where the lands enter thereinto to the breech chamber end thereof, and said groove bore having a portion of constant enlarged diameter between the tapered portion thereof and the breech chamber of the barrel.

23. A projectile propelling apparatus comprising a rifled barrel having a breech chamber, and having a lands bore the diameter of which at the mouth of the barrel is substantially equal to the diameter of the body of a flanged projectile which the barrel is designed to fire, whilst the groove bore is, at'the mouth of the barrel, a normal amount greater in diameter than the lands bore, said groove bore being substantially constant for a distance from the mouth of the barrel and then increasing in diameter in a direction towards the breech chamber and then being of a constant enlarged diameter over a further portion of its length, said lands bore also being increased in diameter in a direction towards the breech chamber and the lands being at all places in their length of a greater absolute height (from the groove-bottoms to the top of the lands) than the minimum height required to prevent the flanges of the said projectile shearing from the lands in its passage through the barrel under the action of a given propellant, and a given charge, the said varying absolute lands heights being determined. with reference to the curve showing the specific lateral pressures with which the flanges of the said projectile will, in passing through the barrel under the action of the respective propellant and charge, bear on the flanks of the lands.

24. A projectile propelling apparatus comprising a rifled barrel the lands bore calibre of which is at the muzzle of thebarrel substantially equal to the calibre of the body of the projectile which the barrel is designed to fire, and the groove bore of which barrel is at the muzzle thereof normal for the said lands calibre, said lands and groove bores being in their lengths increased gradually in diameter in a direction towards the breech end of the barrel but said bores increasing at different rates of taper to one another so that the lands attain a maximum height (which height is greater than the absolute height of the lands at the muzzle), and the lands then continuing at this height up to a point where they terminate,'at those ends nearest the breech chamber, abruptly from their maximum absolute heights.

25. Projectile propelling apparatus comprising a barrel having a breech chamber and in addition to the latter a bore consisting of three end to end coaxial sections, namely, a cylindrical muzzle section remote from the breech chamber and of substantially normal dimensions for the calibre of the body proper of the projectile for which the barrel is designed, an enlarged cylindrical section adjacent and following the breech chamber and such enlarged cylindrical section being between 20% and greater in cross sectional area than the said muzzle section, and an inteimediate section connecting the said cylindrical and muzzle sections together and being relatively long as compared with said other sections and decreasing in diameter in a single continuous taper from the diameter of the said. enlarged cylindrical section to the diameter of the muzzle section.

26. Apparatus for propelling projectiles having a body provided with axially spaced outwardly extending peripheral depressible flanges, comprising a barrel having a bore provided with rifling and in which bore the lands calibre at the muzzle is substantially equal to the diameter of said projectile body whilst the groove bore at the muzzle is normal for such lands calibre, the groove and lands bores both being increased in diameter gradually between the ends of the bore and in a direction away from the muzzle of the barrel, said lands being at a part between their ends of greater absolute height than they are at the muzzle, and said rifiing having a progressive angle of twist.

27. Projectile propelling apparatus comprising a barrel having a partly rified bore, the lands bore being at the muzzle of the barrel of a diameter substantially equal to that of the body of a flanged projectile that the barrel is designed to fire whilst the groove bore at the muzzle is normal for such lands bore, said groove and lands bore being substantially cylindrical for a distance from the muzzle and each increasing in diameter gradually in a direction away from the muzzle, the lands bore having a lesser angle of taper relative to the axis of the bore than the groove bore, the lands attaining, at a distance from the muzzle, greater absolute heights than they have at the muzzle, and then these lands being gradually decreased in height in a direction away from the muzzle and entering the groove bore in the tapered part thereof, such groove bore having an enlarged cylindrical section extending rearwardly from the rear and larger end of its tapered section.

HERMANN GERHCH.