US3291048A

US3291048A - Practice projectile for sub-calibre barrels

Info

Publication number: US3291048A
Application number: US445935A
Authority: US
Inventors: Lubbers Willi
Original assignee: Nico Pyrotechnik Hanns Juergen Diederichs GmbH and Co KG
Current assignee: Nico Pyrotechnik Hanns Juergen Diederichs GmbH and Co KG
Priority date: 1965-02-24
Filing date: 1965-04-06
Publication date: 1966-12-13
Anticipated expiration: 1983-12-13

Description

Dec. 13, 1966 w. LUBBERS 3,291,043

PRACTICE PROJECTILE FOR SUB-CALIBRE BARRELS Filed April 6, 1965 United States Patent 3,291,048 PRACTICE PRGJECTILE FOR SUB-CALIBRE BARRELS Willi Lubbers, Trittau, Bezirk, Hamburg, Germany, as-

siguor to Nico-Pyrotechnik Hanns-Jurgen Diederichs KG., Hamburg, Germany Filed Apr. 6, 1965, Ser. No. 445,935 3 Claims. (Cl. 102-41) The present invention relates to a practice projectile, particularly for a sub-calibre barrel which can be used advantageously, for instance, for mortars.

With this practice projectile, particularly good precision in shooting is obtained, since such projectiles, despite the unfavorable charge-weight ratio, have a particularily small dispersion and a uniform range.

Ordinarily the mouth of the cartridge case is crimped onto the head of the projectile. There results from this a large number of uncontrollable conditions which makes the force necessary to drive the projectile out of the case differ greatly from one projectile to another, or in other words, the tamping of the projectile differs greatly and accordingly also its dispersion and range.

In accordance with the invention, a very precise fastening of the projectile in the projectile case is obtained by arranging between the rear part of the bi-part type projectile which is located in the projectile case and the front part of the projectile (projectile head) which extends out of the case an annular flange which acts as support and is bent over from the front part of the projectile case.

The two parts of the projectile are preferably connected together by screwing. However, it is, of course, also possible to select some other type of connection, for instance, a bayonet lock.

In accordance with one special feature of the present invention, an obturator cap is provided between the propellent charge and the rear part of the projectile, which makes possible a particularly good sealing against the smooth bore of the sub-calibre barrel.

By the embodiment in accordance with the invention, the result is obtained that substantially the same forces are required at all times to separate the projectile from the case, namely, the forces which effect a shearing off of the flanged upper edge of the projectile case.

By the provision of the obturator cap, a uniform action of the propellent charge is at the same time assured.

In this way, it becomes possible to impart each projectile a low dispersion and a range which is the same for all projectiles.

One embodiment of the present invention is shown by Way of example in longitudinal section in the accompanying drawing.

The reference numeral 1 generally designates a subcalibre barrel which, for instance, can have the outer form of a mortar shell and is placed in the firing barrel of the gun in precisely the same manner as a high-explosive shell.

In the lower part of the barrel 1 there is introduced the practice cartridge which consists of the cartridge case 2 and the two parts of the bipartite projectile, namely, the front part 3 and the rear part 4.

The cartridge case is advantageously made of light metal or of a light-metal alloy, for instance, of pure aluminum orif the projectile must be particularly resistant to corrosionof an aluminum-magnesium alloy.

The bipartite projectile terminates at its rear in an obturator cap 5 which can also consist of light metal and the rearward directed side flange 6 of which rests tightly against the inside of the cartridge case and subsequently against the inside of the sub-calibre barrel upon the expulsion of the cartridge as a result of the ignition of the propellent charge 7, thereby providing a particularly good seal.

The propellent charge 7 is ignited in the customary manner by the striking of a pin on the percussion cap 8.

Upon the manufacture of the practice cartridges, after the propellent charge 7 has been introduced, the rear portion or part 4 of the practice projectile is introduced, it consisting of a cylindrical piece of metal in the inner axial bore of which a pyrotechnic charge 9, for instance, can be arranged.

The mechanism 10 which serves for the igniting of the pyrotechnic charge upon the striking of the projectile is unimportant for the description of the invention.

The front widened or counterbored portion 11 of the inner bore of the rear part 4 of the projectile is provided with an internal thread 12.

The side wall of the cartridge case 2 which protrudes slightly beyond the part 4 of the projectile is flanged and forms an inturned flat annular collar or flange 13 which acts as holding ring when the tapered rear portion or coaxially reduced rearward extension 14 of the projectile head or front part 3 is screwed by means of an outer thread 15 on the extension 14 corresponding to the thread 12 into the rear portion 4 of the projectile. The coaxially reduced extension 14 defines with the rear end portion of the body of the part 3 a fiat, annular shoulder, which is in confronting and cooperating relationship with the forward terminal end of the rear part 4, such end defining a shoulder, and the shoulders being flat and clampingly en gaging the interposed fiat annular flange 13, as can be readily appreciated from the drawing. The flange 13 is tightly interposed between the cooperating shoulders and fixed securely therebetween by virtue of the fastening means which connects the

parts

3 and 4 together, such fastening means being in the nature of the cooperating internal threads 12 on the wall of the bore 11 of the rear part 4 and the external threads 15 on the extension 14 of the front part 3.

In conclusion, it should be pointed out that by the embodiment in accordance with the invention, a particularly good sealing is obtained between the projectile and the cartridge case, since the flanged annular collar in the form shown in the drawing serves simultaneously as sealing ring. This is of particular importance in the case of pyrotechnic compositions, since they readily lose effectiveness as a result of the admission of moisture. However, it can be appreciated that, due to the fixed interpositioning of the flat flange 13 between the flat cooperating shoulders on the interlocked front and

rear parts

3 and 4, when the projectile is fired, the flange 13 will be uniformly sheared off and, after the shearing, no undesired loose parts will remain.

What is claimed is:

1. A practice cartridge adapted to be inserted into the firing barrel of a gun comprising a tubular cartridge case having a front end, a two part projectile including a rear part and a front part, said rear part being disposed axially in the case and having a front end formed with an axial bore providing a terminal front end, annular flat shoulder on said rear part, said front part having a rear end terminating in a coaxially reduced rearward extension fitted in the bore of the front end of the rear part, said coaxial extension defining with the body of the front part at the rear end thereof an annular flat shoulder confronting and complementary to the shoulder on the rear part, means securing said front and rear parts together in axial alignment and said cartridge case being formed at its front end with an inturned annular flat flange tightly interposed between the shoulders and held therebetween by virtue of the means securing said parts together, said flange being disposed normal to the aligned axes of the parts and adapted to be sheared 01f upon firing of the projectile.

2. The invention of claim 1, wherein said means securing the parts together comprises interlocking means provided on the extension on the front part and on the wall of the bore in the rear part.

3. The invention of claim 2, wherein said rear part has a rear end, said case being formed with a bore, spaced rearwardly from the rear end of the rear part and adapted to house a propellant charge, said case being formed with a chamber intermediate the rear end of the rear part and the propellant charge and an obturator cap arranged in said chamber and interposed between the rear end of the rear part and the propellant charge.

References Cited by the Examiner SAMUEL FEINBERG, Primary Examiner.

ROBERT F. STAHL, Examiner.

Claims

1. A PRACTICE CARTRIDGE ADAPTED TO BE INSERTED INTO THE FIRING BARREL OF A GUN COMPRISING A TUBULAR CARTRIDGE CASE HAVING A FRONT END, A TWO PART PROJECTILE INCLUDING A REAR PART AND A FRONT PART, SAID REAR PART BEING DISPOSED AXIALLY IN THE CASE AND HAVING A FRONT END FORMED WITH AN AXIAL BORE PROVIDING A TERMINAL FRONT END, ANNULAR FLAT SHOULDER ON SAID REAR PART, SAID FRONT PART HAVING A REAR END TERMINATING IN A COAXIALLY REDUCED REARWARD EXTENSION FITTED IN THE BORE OF THE FRONT END OF THE REAR PART, SAID COAXIAL EXTENSION DEFINING WITH THE BODY OF THE FRONT PART AT THE REAR END THEREOF AN ANNULAR FLAT SHOULDER CONFRONTING AND COMPLEMENTARY TO THE SHOULDER ON THE REAR PART, MEANS SECURING SAID FRONT AND REAR PARTS TOGETHER IN AXIAL ALIGNMENT AND SAID CARTRIDGE CASE BEING FORMED AT ITS FRONT END WITH AN INTURNED ANNULAR FLAT FLANGE TIGHTLY INTERPOSED BETWEEN THE SHOULDERS AND HELD THEREBETWEEN BY VIRTUE OF THE MEANS SECURING SAID PARTS TOGETHER, SAID FLANGE BEING DISPOSED NORMAL TO THE ALIGNED AXES OF THE PARTS AND ADAPTED TO BE SHEARED OFF UPON FIRING OF THE PROJECTILE.