US3424088A - Blank rounds of ammunition - Google Patents

Description

Jan. 28, 1959 Filed May 2. 1967 W. GI'XHLE BLANK ROUNDS OF AMMUNITION Sheet of 5 In vemor Jan. 28, 1969 w, GAHLE 3,424,08

BLANK ROUNDS 0F AMMUNITION Filed May 2, 1967 Sheet 2 of 5 Jan. 28, 1969 w. GAHLE 3,424,08g

BLANK ROUNDS OF AMMUNITION Filed may 2.,1967 Sheet 3 of :5

In ventar: 1% 4% United States Patent 3,424,088 BLANK ROUNDS OF AMMUNITION Walter Gable, Unterluss-Hohenrieth, Germany, assignor to Firma Rheinmetall G.n1.b.H., Dusseldorf, Germany Filed May 2, 1967, Ser. No. 635,520 Claims priority application Germany, May 27, 1966,

R 43,357 US. Cl. 102-39 Int. 01. F421) 5/20, 9/18 9 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to blank rounds of ammunition, in general, and to such blank rounds having a powder charge arranged within a sleeve-like body which may be the shell case and a tamping placed on a cover closing the charge space, in particular.

It is already known to produce blank rounds of this kind by cementing one or more preformed cork plugs into the body or shell case above the powder charge by means of a suitable adhesive, for example shellac. This tamping is intended to be so corn-minuted when the powder explodes that no relatively large particles are projected out of the gun barrel. Moreover, the tamping is intended to be of such a nature that the explosion of the powder produces a loud report which is as similar as possible to the report of a live round. Furthermore, the muzzle flash is to be substantially the same as in the case of a live round.

Also known are shell-case plugs for large-calibre ammunition which consist of a rigid outer jacket portion and a core of soft material. Coarse-ground cork is used in this case to make the soft core and is held together by means of a binder.

The use of such preformed plugs of cork or pressed cork or other suitable material has considerable disadvantages. It is necessary to use plugs which fit very accurately into the body or shell case and care must be taken that the joint with the material of the body or shell case is sufficiently strong. If the joint is not sufliciently strong, relatively large particles of the plug may be projected of the gun barrel and thus endanger persons who are in the vicinity. Moreover, in such a case, the report is not comparable with that of a live round.

To avoid these drawbacks it has been proposed by applicant to make the tamping of a non-preformed pastelike mixture consisting of a filler and a synthetic resin with the addition of a suitable hardening agent for the resin. This paste-like mixture is placed on a cover closing off the powder charge, where it hardens to form an air-tight seal (German patent specification -No. 1,172,578)

It has also been proposed by applicant, in making the tamping, to use a filler which consists of soft vulcanates of natural or synthetic rubber which contain comminuted fibrous materials, for example, the comminution product of the side walls of motor vehicle tires which is known by the name of carcass meal (German patent specification No. 1,198,710).

In another known method of producing a tamping of this kind, the tamping layer is applied by pouring a mixice ture consisting of cork powder or sawdust or like coarse powder or granular material and a cement, for example a plastic cement, this mixture being capable of flowing or trickling into the pre-prepared shell case, i.e., the shell case filled with the powder charge and covered over by means of a cardboard disc, and the tamping layer produced in this way is then hardened by a drying process and thereafter also covered, if necessary, with a protective coating consisting of lacquer or the like (German patent specification No. 1,094,632).

In blank rounds with tampings produced in this way, it has now been found that when atmospheric temperatures are particularly low, fairly large isolated pieces of the tamping material have been projected more than 50 meters from the muzzleof the gun, i.e., passed the recognized safety limit.

It is one object of the present invention to provide blank rounds of ammunition which meet all demands made on these rounds and which, while extremely simpleto manufacture, produce a report very similar to that of a live round, and in fact both in the case of guns with shellcase or cartridge loading and for those guns which are normally loaded with bag ammunition.

It is another object of the present invention to provide blank rounds of ammunition, wherein the tamping consists of a loose mixture of carcass or rubber meal or similar rubber-elastic materials with an addition of a pulverulent material, preferably 5% of said material, with certain lubricating properties, for example, graphite or molybdenum, and is sealed off at the top by a disc of cardboard or some other suitable material which is cemented to the sleeve-like body of the round.

It is still another object of the present invention to provide blank rounds of ammunition, wherein the tamping is divided by means of at least one more cardboard disc or the like which is parallel to the firstmentioned disc, so that there are two layers of the loose tamping material disposed one immediately above the other and merely separated by a cardboard disc.

The total amount of carcass or rubber meal required for the tamping is about 300 gms. in the case of a blank round for a mm. howitzer when there is a single division. The grain size of commercial carcass meal is, for example, of the order of magnitude of 0.5 to 3 mm. The graphite, preferably used because of its cheapness, is finely ground. Instead of this, however, it is also possible to use, for example, molybdenum sulphide, which has similar lubricating or anti-friction properties.

The advantage of the tamping according to the present invention is that even at very low ambient or atmospheric temperatures, no relatively large particles are projected beyond the safe range of 50 meters from the muzzle of the gun barrel. The carcass or rubber meal mixed beforehand with the graphite powder or some other suitable material can be poured in extremely simple manner into the shell case. The fixing of the upper sealing disc and the intermediate cardboard disc does not offer any difiiculty. The advantageous effect of the graphite addition moreover consists in that, on firing, the gun barrel, and in particular the muzzle brake, is given a fine coating of graphite which forms a protection against the hot powder gases. The gun barrel thus has its life prolonged.

The present invention can also be applied with advantage to those blank rounds in which, in order to obtain a loud report with a small charge weight, a compression chamber arranged after tamping is disposed inside a shell case (see for example German patent specification No. 1,113,395). Moreover, it is advantageous to provide a spacer between the powder charge and the tamping for the purpose of maintaining a combustion space which is always of the same size.

The sleeve-like body of the round may either be a shell or cartridge case known per se, to the wall of which the cardboard discs sealing off and dividing the tamping are cemented, or-in particular, in the case of blank shells for large-calibre gunsthe sleeve-like body may be a hollow cylinder consisting of a not readily inflammable plastic material which disintegrates on firing, for example foamed polystyrene, the cardboard discs sealing olf and dividing the tamping being cemented to the hollow cylinder.

In the first case, the spacer may be a hollow cylinder closed at the upper end and which, for example, also consists of foamed polystyrene.

In the second case, the powder charge is contained in a bag which is cemented by part of its wall to the inner surface of the hollow cylinder provided instead of the shell case. The spacer consisting of the same material as the hollow cylinder is then arranged between the powder charge and the tamping, the spacer consisting, for example, of two bridge pieces or bars which are assembled together at an angle to form a cross.

It is yet another object of the present invention to provide blank rounds of ammunition in which the sleevelike body is formed of a hollow cylinder of a not readily inflammable plastic material which disintegrates on firing, and wherein the cardboard discs sealing off and dividing the tamping extend through the wall of the hollow cylinder, and are cemented to the hollow cylinder at their annular surfaces of contact. In this way, the effect of the tamping is increased and this has a favorable action on the report produced and assists the disintegration of the tamping. Furthermore, manufacture of the blank round is further simplified in this way.

The amount of pulverulent lubricant is preferably about by weight of the rubber-elastic material.

With these and other objects in view which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIGURE 1 is an axial section of a blank round having a shell case with a powder charge and a tamping;

FIGURE 2 is an axial section of a blank round with a tamping, but having a cylindrical shell case made of a plastic material, for example foamed polystyrene or the like; and

FIGURE 3 is an axial section of a similar type of blank round with cardboard discs extending through the wall of the round.

Referring now to the drawings, and in particular to FIGURE 1, the blank round comprises a shell case with a calibre of 105 mm. and having a so-called threaded percussion primer 2 and a powder charge 3. The powder charge 3 is housed in the shell case 1 in a hollow cylinder 4 closed at its upper end and consisting of foamed polystyrene. The cylinder 4 has a cover 5 which is either integral with the cylinder 4 or is mounted thereon. Resting on the hollow cylinder 4 is a cardboard disc 6 cemented in and sealed to the wall of the shell case by means of a suitable contact adhesive. The function of the disc 6 may, however, also be performed by a suitable cover 5 for the hollow cylinder 4. Onto the disc 6 there is poured a first layer 7 of tamping material, in the case of the embodiment shown, about 150 gms., of loose rubber or carcass meal with an addition of 5% of graphite powder. Then follows a second cardboard disc 8 on which there is again placed a layer 9 of about 150 gms. of loose carcass or rubber meal with 5% of graphite powder. The conical formation which both the layers 7 and 9 of tamping material take up after pouring is eliminated by light pressure against the tamping material, so that the tamping is given as a whole a cylindrical or disc-shaped form and the cardboard discs press closely against the tamping material. The upper seal of the tamping is formed by a disc 1% of cardboard or some other suitable material which is cemented at its edge to the shell case 1. Then follows also two cup-shaped shell-case covers 11 and 12 which are likewise cemented into the shell case 1 and are spaced apart in manner known per se to form a compression chamber 13 and are sealed with a lacquer or synthetic resin.

Referring now again to the drawings, and in particular to FIG.2, instead of a shell case of metal, the blank round has a sleeve-like body 21 made of foamed polystyrene and into which a powder charge 3 contained in a bag 22 is cemented from inside by means of part of the bag wall. The powder charge 3 has a priming charge 23 on its underside. On that side of the powder charge 3 which faces the tamping there is a spacer 24 of cross-shape, which is preferably likewise made of foamed polystyrene.

The tamping is in exactly the same form as in the embodiment disclosed in FIG. 1 and which has just been described. A lower disc 6 rests on a shoulder 25 of the polystyrene sleeve 21, to which the disc 6 is cemented at its edge, and to the spacer 24. Above the disc 6, which preferably consists of cardboard, there is a first layer 7 of tamping material consisting of loose carcass or rubber meal with about 5% of graphite mixed therewith. Then follows an intermediate disc 8 above which there is disposed another layer 9 of tamping material consisting of loose carcass or rubber meal with about 5% of graphite. The upper sealing disc 10 is covered by another disc 26 which is cemented at its edge onto the end face of the polystyrene sleeve 21. In a blank round constructed in accordance with FIG. 2 and for a calibre of 203 mm., about 625 gms. of tamping material are used for each layer of tamping material, that is a total of about 1250 gms. of material was used for the tamping.

Referring still further to the drawings, and in particular to FIG. 3, the embodiment of the present invention disclosed in this figure differs from that shown in FIG. 2 in that the cardboard discs 6, 8 and 10 sealing off and separating the tamping layers extend through the wall of the hollow cylinder 21, so that two similar tamping layers 27, 28 are formed, these being cemented at their annular surfaces of contact to the cardboard discs and the sleeve body 21.

While I have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. A blank round having a powder charge comprising a sleeve-like body defining at its bottom a chamber adapted to receive a powder charge,

means secured to said sleeve-like body and sealing off said chamber,

a tamping disposed in said sleeve-like body and comprising a loose mixture of materials selected from the group consisting of carcass meal, rubber meal and rubber elastic material, with an addition of pulverulent material having lubricating properties, and

a disc secured to said sleeve-like body and sealing off said tamping at the top.

2. The blank round, as set forth in claim 1, which includes at least one further disc dividing said tamping and disposed in parallel relationship to said first-mentioned disc.

3. The blank round, as set forth in claim 2, wherein said discs are of cardboard.

4. The blank round, as set forth in claim 2, wherein said sleeve-like body comprises a hollow cylinder of a not readily inflammable plastic material having the property of disintegrating on firing, and

said discs sealing off and dividing said tamping are cemented to said hollow cylinder.

5. The blank round, .as set forth in claim 4, wherein said hollow cylinder is of foamed polystyrene.

6. The blank round, as set forth in claim 4, wherein said discs extend through the wall of said hollow cylinder and are cemented to said hollow cylinder at their 9. The blank round, as set forth in claim 1, wherein annular surfaces of contact. said pulverulent material is added to the extent of about 7. The blank round, as set forth in claim 1, which in- 5% by weight of said loose mixture of materials.

cludes spacer means disposed between said chamber and said 5 References C'ted tamping, in order to maintain a combustion space of UNITED STATES PATENTS always the same size for the powder charge. 3 148 620 9/1964 Jacobson et 102 38 8. The blank round, as set forth in claim 1, wherein 3209689 10/1965 McLennan 102 38 said pulverulent material consists of a material se- 3295448 1/1967 Gable lected from the group consisting of graphite and 10 molybdenum. ROBERT F. STAHL, Primary Examiner.

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