US3442214A

US3442214A - Shotgun cartridge

Info

Publication number: US3442214A
Application number: US629514A
Authority: US
Inventors: Joseph Walter Huskins
Original assignee: Imperial Metal Industries Kynoch Ltd
Current assignee: Imperial Metal Industries Kynoch Ltd
Priority date: 1965-05-24
Filing date: 1967-04-10
Publication date: 1969-05-06
Anticipated expiration: 1986-05-06
Also published as: ES327101A1; DE1302027B; GB1115722A; DE1926129U; AT271267B

Description

y 6, 1969 J. w. HUSKINS 3,442,214

SHOTGUN CARTRIDGE Filed April 10. 1967 Sheet of 2 I/I/I/I/I May 6, 1969 Filed April 10, 1967 J. W. HUSKINS SHOTGUN CARTRIDGE /I// I/I/I/I/I/ Unite States US. Cl. 102-42 8 Claims ABSTRACT OF THE DISCLOSURE A shotgun cartridge having a cartridge case of polymeric material, a crimp type closure, and a frangible card etween the closure and the shot charge whereby bulging of the case during crimping is obviated.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 475,636 filed July 29, 1965, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to shotgun cartridges having crimp type closures.

Description of the prior art In the manufacture of shotgun cartridges, a convenient method of retaining the shot charge is to crimp the open end of the cartridge case inwardly over the shot. This is known as a flute crimp closure which can be an internal flute crimp or a raised flute crimp in accordance with the direction of projection of the flutes from the closure. During the crimping operation for an internal crimp closure, each flute of the crimp closure wedges downwardly into the shot to press the shot in directions away from each fiute and to cam the shot longitudinally of the flute towards the wall of the cartridge case. When the case is formed from cardboard the movement of the shot against the wall of the case is tolerable. However, when the wall of the cartridge case is of a polymeric material which is highly flexible in comparison with cardboard, such as high density polyethylene for example, the displacement of the shot produced by the action of each flute produces a highly objectionable bulging to the wall of the case immediately below the crimp closure. This bulging is unsatisfactory from a practical point of view, since it may impede insertion of the cartridge into the breech of a gun, and also leads to a product of unsatisfactory appearance.

To minimize the problem as much as possible, resort has had to be made to the procedure of thickening the wall of the case, at least in the vicinity of the crimp closure, whereby greater stiffness is provided and the bulging effect is reduced. This expedient is wasteful of the material of the case and can lead to complications in tooling. Moreover, the interior volume of the case available for shot is reduced.

The same problem of shot bulging can also arise for raised flute crimp closures because of the outward displacement of shot caused by the segments of the closure between the raised flutes.

SUMMARY According to the present invention, comprises a flexible cartridge case of polymeric material, shot contained within the cartridge case, a flute crimp closure to the cartridge case covering substantially the whole area of the end of the cartridge case to retain the shot charge, and an over-shot card of frangible material located between the shot and the crimp closure thereby preventing radial displacement of the shot during crimp closure to obviate bulging of the flexible wall of the cartridge case.

We have found that if a frangible over-shot card is provided beneath the normal crimp closure, this card effectively prevents displacement of the shot radially of the cartridge during crimp closure. Consequently, the shot is not pressed to an inordinate degree against the interior of the wall of the case and the wall does not have to be thickened or in any way reinforced to prevent it from bulging.

DESCRIPTION OF THE DRAWINGS FIGURE 1 is an axial cross-sectional view of a cartridge according to a first embodiment;

FIGURE 2 is a similar view to that of FIGURE 1 part of a cartridge forming a second embodiment; and FIGURES 3 and 4 are reproductions of photographs of cartridges having crimp type closures and provided with and without frangible over-shot cards respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a first embodiment, as shown in FIGURE 1, a shotgun cartridge as shown in the drawing has a cartridge case 1 comprising a cup-shaped metallic head 2 and a tube 3 of flexible polymeric material which, in this embodiment, is high density polyethylene, one end of the tube being held within the metallic head. A primer 4 is mounted in a central aperture of the metallic head.

The cartridge case contains a powder charge 5, separated from the metallic head by a base wad 6, a wadding column 7, and metallic shot 8 which is separated from the powder charge by the wadding column. A frangible over-shot card 9 made from granulated cork, impregmated with paraflin wax to make the card impermeable, is located above the metallic shot. The end 10 of the polyethylene tube remote from the metallic head is crimped over the over-shot card to form a closure and cover substantially the whole of the card, This type of crisp closure is known in the trade as an internal flute crimp closure and is produced by a tool which forms the end of the tube into equiangularly spaced, inwardly directed, flutes. In the present embodiment six flutes are formed.

It is found that because an over-shot card is provided in the cartridge described above, the metallic shot is not displaced radially relative to the axis of the cartridge during crimping so that there is no resultant tendency for the flexible wall of the tube to bulge radially outwards in the regions adjacent the crimped closure.

Therefore, as there is no tendency for the flexible tube of a cartridge according to the invention to bulge radially outwards, the thickness of the tube wall is not infiuenced by any required stiffness to prevent bulking.

Further, in the cartridge of the invention, water, moisture or other harmful foreign matter which may enter the cartridge through any small space remaining in the crimped end closure, cannot pass through the card to reach the metallic shot. In addition, as the card is formed from cork in the first embodiment, it is resilient and compressible so that, during crimping, it is compressed by the flutes in the tube substantially to assume the shape of a shotgun cartridge he inner surface of the crimped end closure, as shown n the drawing, so that it lies substantially in intimate :ealing engagement with this inner surface. An effective 831 is, therefore, provided between the cork card and he crimped end closure which substantially prevents noisture or other foreign matter from passing around :he card into engagement with the metallic shot. These advantages, of course, are not obtainable with convenional cartridges having crimped end closures as moisture or other harmful matter may enter the cartridge, through inevitable holes which are formed in the end closures, and into direct contact with the shot.

Moreover, although the cartridge as described in the first embodiment has the above advantages over conventional constructions, the provision of the over-shot card does not adversely affect the performance of the cartridge as the card disintegrates into relatively small particles upon firing so that it cannot deflect the shot from its true trajectory. The disintegration may be assisted by weakening the card with knife cuts or by using a rammer having one or more knife edges to insert the card in the cartridge case before the crimping operation.

In a second embodiment shown in FIGURE 2, a cartridge 11 is of a construction similar to that of the first embodiment except that the cork over-shot card is replaced by a polystyrene over-shot card 12 having a grooved surface 13 to weaken the construction and thus render it frangible. This cartridge has the advantages of the cartridge of the first embodiment, except that in this present case, as the plastic does not possess the degree of compression of cork, the seal provided between the over-shot card and the crimped end closure is less effective than that formed between the cork over-shot card of the first embodiment and the crimped end closure.

The result of our invention is clearly shown by a comparison of FIGURES 3 and 4 which are representations of photographs of cartridges having cases of polymeric material, of the same wall thickness, and provided with internal flute crimp closures. FIGURE 3 shows the result of providing a frangible over-shot card between the shot and the flute crimp closure and it is clear from the smooth external contour of the cartridge that bulging has not occurred during crimping. In contrast FIGURE 4 illustrates the bulging of a case produced by the shot contained therein when crimping is effected without the provision of an over-shot card. Thus, by employing an overshot card under the crimp closure, the manufacturer does not have to resort to using a thicker material for the cartridge case but is enabled to retain a thin wall for the case.

I claim:

1. A shotgun cartridge comprising a flexible cartridge case of polymeric material, shot contained within the cartridge case, a flute crimp closure to the cartridge case covering substantially the whole area of the end of the cartridge case to retain the shot charge, wherein the improvement comprises an over-shot card of frangible material which disintegrates into relatively small particles upon firing so that it cannot deflect the shot from its true trajectory, said over-shot card being located between the shot and the crimp closure thereby preventing radial displacement of the shot during crimp closure to obviate bulging of the flexible wall of the cartridge case.

2. A shotgun cartridge according to claim 1 having the over-shot card formed from granulated cork.

3. A shotgun cartridge according to claim 2 wherein the granulated cork card includes a substance to render the card impermeable.

4. A shotgun cartridge according to claim 1 having the over-shot card formed from a plastics material.

5. A shotgun cartridge according to claim 4 wherein the plastics card is weakened by grooves in one surface thereof.

6. A shotgun cartridge comprising a flexible cartridge case of polymeric material, shot contained within the cartridge case, an internal flute crimp closure to the cartridge case covering substantially the whole area of the end of the cartridge case to retain the shot charge, wherein the improvement comprises an overshot card of frangible material which disintegrates into relatively small particles upon firing so that it cannot deflect the shot from its true trajectory, said over-shot card being located between the shot and the crimp closure thereby preventing radical displacement of the shot during crimp closure thereby preventing radial displacement of the shot during crimp closure to obviate bulging of the flexible wall of the cartridge case.

7. A shotgun cartridge comprising a flexible cartridge case of polymeric material, said case being highly flexible in comparison with cardboard and having its outer end crimped to form a crimp closure covering substantially the whole area of the end of the cartridge case, the wall of the cartridge case being of uniform thickness at least along its outer end portion, shot contained within the cartridge case, and means for reducing the tendency of the cartridge case to bulge radially outwardly due to radial displacement of the shot during crimping of the cartridge case, said means including a frangible over-shot card which disintegrates into relatively small particles upon firing so that it cannot deflect the shot from its true trajectory, said over-shot card being located between the shot and the crimp closure.

8. A shotgun cartridge as in claim 7 wherein said case is constructed of high density polyethylene.

References Cited UNITED STATES PATENTS 2,189,498 2/1940 Spengler 102-42 2,232,634 2/1941 Roberts et al 102-42 2,842,057 7/1958 Dunn 102-42 3,215,075 11/1965 Bayard et al. 10242 3,295,448 1/1967 Gahle 102--95 X 3,354,571 11/1967 Parker 10295 X FOREIGN PATENTS 692,169 7/1930 France.

1,009,415 3/ 1952 France.

VERLIN R. PENDEGRASS, Primary Examiner.

, US. Cl. X.R.