SHOTGUN SLUG CARTRIDGE

Abstract: A cartridge which is particularly suitable for use in smooth bore guns where greater accuracy is desired by virtue of a gyroscopically stable rifling projectile, achieved by a bearing for the projectile, which overcomes the resistance to turn against the wad or gas sealing member normally encountered in a conventional shotgun cartridge. The invention allows the shooter to use a shotgun as both an accurate rifle or a conventional shotgun by simply changing the cartridge in use. It comprises a projectile body part (15), a bearing (18) and (19) and a wad or gas sealing member (20).

Description: Shotgun slug . t ' '■ • "N Description of Invention This invention relates to bul lets and more part icularly, but not exclusively, to bullets which may be fired from π shotgun. The barrels of shotguns usually have smooth bores and hence, whilst being suitable for firing pellets which prior to firing are contained in a 5 cartridge case, are not readily suitable for fi ring bullets which require generally, a rifled bore to impart a rotation to the bullet as it leaves the barrel, to prove accuracy of the trajec tory thereof. It has been proposed to provide ri f ling on the exterior surface of the bullet. However, in a shotqun, it is necessary to provide in the cortridge, a ' " gas sealing member usually comprising a wad of f ibr ous material, > « /hich passes along the barrel behind the pellets when the cartridqe is fil ed. Where a bullet is fired, the wad is still required for gas s c aling, but t his tends to provide resistance to the rotation of the bullet which is imparted by Ihe rifling. • 5 Accordingly it is an object of the present invention to provide a new or improved bullet which overcomes this problem According to one aspect of the inven t ion we provide a bul let having, or being adapted to receive, a bearing. Thus the bearinq may be engaged by a spacing means, which may a " 20 i he bul let from the gas sealing member. Thus rotation of the bul let as i t passes along the bore, is not inhibited by any f ric i ional contac t between the gas sealing member and the bullet. Preferably, the exterior surface of the bullet is rif led. The bearing may be provided in o" interior hollo// of the bul let hich 25 may be made of lead or any other material. According to a second aspect of the invention we provide in combination, a bullet and a qas sealinq member, means maintaining separation of the bullet and the gas sealing member and permi t ting of relative rotation between the bullet and the gas sealing member. Thus there 30 is no frictionαl contact between the bullet and the gas sealing member to inhibit rotation of the bullet relative to the gas sealing member. Preferably, the bullet receives a bearing, which is engaged by a spacing means, although alternatively the gas sealing member may receive a bearing which is engaged by a spacing means. Further alternatively, the bullet and the gas sealing member may have mutualfy engageable bearing parts. In each case, preferably the bullet and the gas sealing member can separate once the bullet and gas sealing member have left the barrel of the gun from which they are fired so that the gas sealing member does not provide resistance in the air to the trajectory of the bullet. In one embodiment, the bullet may have a recess in which the bearing is received, and the gas sealing member may have a projecting part which provides said spacing member and engages with the bearing. For example, the bearing may comprise a ball bearing and the projecting part of the gas sealing member may engage the surface of the ball bearing. The recess may be of a corresponding shape to the ball bearing, and the ball bearing may therefore rotate relative to both the bullet and the projecting part. In another embodiment, the bearing may comprise a pcir of engaging elements, such as plates, one of the elements being received by the bullet, and the other element by the gas sealing member, the elements together being of such dimension that the bullet is separated from the gas sealing member, and providing low resistance to relative rotation. For example, the contacting surfaces of the elements may be coated with a low friction material such as Teflon. Many other arrangements are no doubt possible. The gas sealing member may comprise a wad of fibre like material, or a wad of nylon. Where the gas sealing member has a projecting part which engages with the bearing of the bullet, the projecting part may comprise a metallic insert or an insert of another material giving low frictional resistance where the projecting part engages the bearing. The gas sealing member may be constructed in two parts attached together, with a part of the projecting part received therebetween. According to a third aspect of the invention we provide a cartridge for a shotgun, the cartridge including a combination of a bullet and gas sealing member according to the second aspect of the invention. The invention will now be described with the aid of the accompanying drawings in which: FIGURE I is α side cross sectional view of a cartridge having a bullet and gas sealing member combination in accordance with the invention. FIGURE 2 is a cross sectional view through the barrel of a shotgun showing a bullet and gas sealing member combination in accordance with the 5 invention. FIGURE 3 is a further side view, partly in section, of a still further bullet and gas sealing member combination in accordance with the invention. 'f Referring first to Figure I , a cartridge 10 for firing in a shotgun, comprises a cartridge case 1 1 made of paper, plastic, or another material, 10 and a, usually brass, cap 12 which has in the centre thereof a firing pin 13 which is adapted to be struck by a hammer of a firing mechanism of the shotgun. The cartridge 10 has a charge 13' which is ignited when the pin 13 is struck. 15 The cartridge case I I has projecting from one end 14 thereof opposite to the end on which the cap 12 is provided, a bullet 15 having a conventional tip 16. However, the bullet 15 has an internal recess 17 which receives a bearing 18, which in the present example comprises a steel ball. The ball 1 8 is engaged by a spacing member comprising a projecting part 19 of a gas sealing 20 member 20. The gas sealing member comprises a first part 2 1 of a fibrous material, and a second part 22 also of a fibrous material, the part 22 having an internal recess 23 in which a transversly extending base part 24 of the projecting part 19 is received, so that the base part 24 is trapped between the parts 21 and 22 of the member 20. 25 When the charge 13* is ignited, the bullet 15 and gas sealing member 20 are ejected from the cartridge case 1 1 by the expanding exploding gases, and Will pass together along the barrel of the shotgun, the gas sealing member 20 expanding outwardly to provide a gas tight seal with the internal bore of the barrel so that the expanding exploding gases cannot pass the gas sealing 30 member 20, but urge the gas sealing member 20 and the bullet 15 together, from the barrel of the gun. The bullet 15 preferably has rifling on the exterior surface thereof (which is not seen in Figure I ) so that a rotation is imparted to the bullet 1 5 as it moves along the barrel. 35 The bullet 15 rotates relative to the gas sealing member 20 by virtue of the bearing 18 and the projecting part 19 which permit relative rotation therebetween with minimum frictional resitance. When the bullet 15 and gas sealing member 20 leave the barrel of the gun, the bullet 15 and member 20 will separate, so that the member 20 will not provide resistance to the flight of the bullet 15 through the air, to its target. This is permitted because the projecting part 19 simply contacts the ball 18 and can readily separate therefrom. Referring now to Figure 2, an alternative embodiment is shown. The barrel of a gun is illustrated at 25 with a bullet 15', which is not shown in section and so rifling 26 is visible on the exterior surface thereof, along with a gas sealing member 20' passing along the barrel 25. The bullet 15' again has an internal recess 17' but of a different configuration to recess 17 of the bullet 15 of Figure I . The recess 17' is arranged to receive a keyed bearing element 27 comprising a plate which is dimensioned to project from the recess 17'. The plate 27 is prevented from rotating relative to the bullet 15* by means of keyways 28 provided in the bullet in which corresponding projecting portions of the bearing plate 27 are received. The bearing plate 27 presents a lower surface 39 coated with Teflon or another low-friction coating, and is engaged by a further bearing element comprising a further plate 30, which provides an upper surface 31 , also coated with Teflon or the like, whereby bearing parts 27 and 30 can rotate relative to one another with a minimal frictional force. " The plate 30 is dimensioned to project from the member 20' so that the plates 27, 30, together provide not only a bearing, but a spacer means to separate the member 20' from the bullet 15'. The gas sealing member 20' again comprises a wad of fibrous material but could be made in other materials if required. It can be seen that the exterior surface of the gas sealing member 20' is in gas tight engagement with the internal bore of the barrel 25. Again,when the bullet 15' and sealing member 20' leave the barrel of the gun, they will separate as the surfaces 29, 31 , simply contact one another. Referring now to Figure 3, a still further exteriorly rifled bullet 15", and gas sealing member 20" combination is shown, which is similar to the bullet 15 and gas sealing member 20 combination of Figure I. However the recess 17" provided within the bullet is much larger than the recess 17 of Figure I , and the bearing 18", which again comprises a ball, is again much larger than the ball 18 shown in Figure I . The gas sealing member 20" comprises a first part 21 " made of nylon, which has a skirt 32 which expands outwardly resiliently into engagement with the internal bore of the barrel 25 to provide a seal, and a second part 22" of nylon which entraps a base part 24" of a projecting part 19" which engages with the ball 18". It will be appreciated that in the Figure I embodiment, as the bullet 15 is urged along the barrel of the gun by the exploding gases engaging the gas sealing member 20, a force is exerted through projecting part 19 to the ball 18, and the ball 18 will thus tend to be urged forwardly out of the recess 17 into the bullet 15 itself. Particularly where the bullet 15 is made of a soft material such as lead, and the ball 18 is made of a harder material such as steel, there is a risk that the ball 18 will be pushed so far into the bullet 15 that the rearwardmost surface 42 of the bullet 15 will be engaged by the forwardmost surface 43 of the gas sealing member 20. This would result in a frictional contact which would inhibit rotation of the bullet 15 and thus the trajectory of the bullet may be affected after the bullet 15 leaves the barrel, as the bullet will lack gyroscopic stability which can only be obtained if adequate rotation to the bullet is imparted. Accordingly, in the Figure 3 embodiment, because the areas of the contacting surfaces of the ball 18" and the recess 17" of the bullet 15" are larger the possibility of the ball 18" being urged out of the recess 17" is reduced compared with the arrangement shown in Figure I. Various modifications may be made to the embodiments described without departing from the scope of the invention. For example, instead of a bearing being provided in a recess in the bullet as in Figures I and 3, if desired a projecting part of the bullet may engage with a bearing received by the gas sealing member. The bullet and gas sealing member need not be of the exact configurations shown, but the bullet could have a different configuration tip 16, such as a pointed tip for example. Although the invention has been described in relation to a shotgun from which a bullet is fired by an explosive charge, the invention could of course be applied to bullets for other guns, such as air guns, which may have a smooth internal bore.

Claims: CIAIMS 1 A cartridge comprising a bullet and a wad or gas sealing member, being assembled together but separated by a bearing and the rotation of the skirt or base of the bullet, not being inhibited by any contact with the gas sealing member or device. 2 A cartridge as claimed in 1 wherein the separating bearing is either a ball bearing, roller bearing, non-frictional surface to surface bearing, or the surfaces of the bullet and gas sealing device coated with a substance or lubricant to reduce friction between the one or multiplicty of projectiles and it's gas sealing device or wad. i 3 A cartridge as claimed in 1 & 2 with a bullet that has rifling or grooves on it's exterior surface, thereby promoting rotational spin to the projectile in the bore of a gun only impeded or inhibited by the minimal frictional force of it's launching or gas sealing device. 4 A bullet as claimed in 1 to 3 which is fired from a cartridge or together as a bullet and a wad from a gun barrel not contained in a cartridge case by an explosive charge or compressed air or mechanically spring assisted. 5 A bullet as claimed in 1 to 4 fired from a gun barrel which has either internal rifling grooves or smooth internal bore. 6 A bullet and wad substantially as herein before described with reference to and as illustrated in the accompanying drawings and text.

Inventors: JOHNSON PETER IAN, JOHNSON, PETER, IAN
Applicants: JOHNSON PETER IAN, JOHNSON, PETER, IAN
Application year: 1986
Main classification: F42B7
IPC codes: F42B7