WO2000034732A1

WO2000034732A1 - Ammunition

Info

Publication number: WO2000034732A1
Application number: PCT/IB1999/001949
Authority: WO
Inventors: Mark Hamilton Kay-Clough
Original assignee: Kay Clough Mark Hamilton
Priority date: 1998-12-08
Filing date: 1999-12-07
Publication date: 2000-06-15
Also published as: GB0116362D0; AU1402400A; WO2000034732B1; GB2367349A

Abstract

A projectile (130) for a cartridge (200) includes a projectile body (14) and mounting means for removably mounting the projectile body (14) to a cartridge case (202). The mounting means includes a mounting formation (7) which projects from a base of the projectile body (14) and which has a smaller maximum transverse dimension than a maximum transverse dimension of the projectile body (14). The invention extends to a cartridge case (202), a cartridge (200) and protection means (140) for protecting a primer (232) of a cartridge.

Description

AMMUNITION

THIS INVENTION relates to ammunition. In particular, it relates to a projectile, to a cartridge case, to a cartridge, and to protection means for protecting a primer of a cartridge.

According to a first aspect of the invention, there is provided a projectile for a cartridge, the projectile including a projectile body and mounting means for removably mounting the projectile body to a cartridge case, the mounting means including a mounting formation which projects from a base of the projectile body and which has a smaller maximum transverse dimension than a maximum transverse dimension of the projectile body.

In other words, when seen from a rear or trailing end of the projectile, the mounting formation falls wholly within the outline of the projectile body.

The projectile body may be elongate and circular in outline in end view and the mounting formation may be elongate and circular in cross section. The mounting formation may be substantially circular cylindrical over at least a major portion of its length. Thus, the mounting formation may have a maximum diameter which is smaller than the maximum diameter of the projectile body.

The maximum transverse dimension of the mounting formation may be at least half the maximum transverse dimension of the projectile body, but smaller than that of the projectile body by a sufficient margin to ensure that the mounting formation does not interfere with the rifling of a barrel when the projectile body is fired through a rifled barrel dimensioned in conventional manner for the caliber of the projectile. For small caliber cartridges of less than 8mm diameter, the mounting formation typically has a diameter greater than or equal to half the maximum diameter of the projectile body.

A ratio of the maximum transverse dimension of the mounting formation to the maximum transverse dimension of the projectile body may be between 0,5: 1 and 0,95: 1 . Preferably the ratio of the maximum transverse dimension of the mounting formation to the maximum transverse dimension of the projectile body is between 0,75: 1 and 0,95: 1 .

The mounting formation may be integral with the projectile body. Instead the mounting formation may be a separate body attached to the projectile body. The mounting formation may thus be in the form of an insert which extends into the projectile body and which projects away from a rear or trailing end of the projectile body. About two thirds of the length of the insert may then be located inside the projectile body, with one third projecting away from the rear end or base of the projectile body. However, it is to be appreciated that this arrangement is dependent on the size and shape of the projectile, and that the overriding concern is the balance of the projectile during flight when fired. The ideal arrangement for a particular projectile or caliber can be determined by routine experimentation.

In one embodiment of the invention, the mounting formation is in the form of a circular cylindrical elongate insert frictionally located in a blind-ended passage extending from the base of the projectile body into the projectile body and co-axially aligned with the projectile body. In another embodiment of the invention, the mounting formation is in the form of an elongate insert extending coaxially through the projectile body, the insert defining a nose of the projectile.

The insert may define a retaining formation cooperating with a complimentary retaining formation defined by the projectile body, thereby to secure the projectile body to the insert.

The retaining formation defined by the insert may include a cannelure. The cannelure may include at least one spline or key. The spline may be straight, or it may be angled at between 1 ,5 ° and 3 ° relative to a central longitudinal axis of the projectile. Typically, a plurality of splines is provided. The splines are preferably angled in the same direction (clockwise or counter clockwise) as the rifling of a barrel through which the projectile is to be fired.

The mounting formation may be of a material selected from the group consisting of solid metals, alloys, ceramics, and solid synthetic plastics or polymeric materials. Examples of suitable materials for the mounting formation are stainless steel 304, 31 6, 321 , 310, copper, lead jacketed in copper, ceramics, treated steels EN30B or EN36B, aluminium and tungsten carbide. The mounting formation should thus be of a material which is hard and which will not break up when subjected to the pressures in a barrel when fired through the barrel. In one embodiment of the invention, the mounting formation is of a solid synthetic plastics or polymeric material, such as a nylon. The mounting formation may be formed by drop forging, casting, pressing, machining or cutting to length.

Preferably, the projectile body should have a large enough peripheral portion which engages an inside of a barrel through which the projectile is fired in use, to ensure that the mounting formation stays axially aligned with the barrel as the projectile moves through the barrel.

The projectile body may be of any material conventionally used for projectiles of cartridges, and may be machined, pressed, drop forged or injection molded. The projectile body may thus be of a material selected from the group consisting of solid metals, alloys, and solid synthetic plastics or polymeric materials. These materials should readily accept rifling in the barrel and minimize fouling of the barrel, and should be relatively soft. Examples of material for the projectile body are copper, copper alloys, oil impregnated nylon, nylon, and iron alloys with a copper or copper alloy jacket. In one embodiment of the invention, the projectile body is of a solid synthetic plastics or polymeric material, such as a nylon, which may be molded around the mounting formation. The nylon projectile body, when cut to specific angles can be made to act as a conventional sabot to break off the mounting formation shortly after leaving a barrel from which the projectile is fired. The mounting formation will then become a bullet or projectile with high velocity and energy.

A rear or trailing surface of the mounting formation, remote from the projectile body, may be concavely curved or inwardly domed. This advantageously directs the force exerted by propellant gas towards the center of the mounting formation, and enhances the creation of a vacuum during flight of the projectile.

The mounting formation may be configured to mount the projectile body to a cartridge case by means of a friction fit between the mounting formation and the cartridge case. The projecting portion of the mounting formation may thus be shaped to enhance the friction fit between the mounting formation and a cartridge case. An end of the mounting formation remote from the projectile body may be beveled or the like to facilitate insertion of the mounting formation in the cartridge case. The mounting formation may have serrations or ridges or corrugation or recesses or the like to enhance friction between the mounting formation and the cartridge case and/or between the mounting formation and the projectile body, which may have complimentary formations.

The projectile may be balistically tipped.

According to a second aspect of the invention, there is provided a cartridge case which is elongate with a central passage extending therethrough and which is open at both a projectile mounting end for mounting a projectile to the cartridge case such that it projects from the cartridge case, and a primer mounting end, a primer housing for housing a primer being fitted to the primer mounting end of the cartridge case.

The primer housing may have a substantially cylindrical portion fitting with a friction fit into the primer mounting end of the cartridge case. When the cartridge case is of a solid metal or alloy, the primer housing may thus be press fitted into the case. The cylindrical portion may be serrated or corrugated to better grip against the cartridge casing, which may have oppositely directed serrations or corrugations.

The cartridge case may include sealing means for inhibiting escape of pressurized gas, in use produced by combusted propellant inside the cartridge case, from the cartridge case between an interior surface of the cartridge case and the primer housing.

The sealing means may include a deflector for in use inwardly deflecting pressurized gas moving towards the primer mounting end of the cartridge case away from the interior surface of the cartridge case towards a central longitudinal axis of the cartridge case.

The deflector may define a frusto-conical surface opening out towards the projectile mounting end of the cartridge case. Instead, it may define a concavely curved or inwardly domed surface. The deflector may have a central aperture and may be deformable such that in use it is deformed or forced against the interior surface of the cartridge case by the pressurized gas.

The sealing means may include a deformable seal abutting against the primer housing and located inside the cartridge case. The seal may have a central passage and being arranged such that in use it is forced against the primer housing and the interior surface of the cartridge case by the pressurized gas. Examples of suitable material for the seal is urethanes, PTFE, Desmopan, Teflon, nitrile, or the like. The seal must be able to withstand the high temperatures generated in a cartridge case and must fit snugly in the cartridge case. A typical hardness for the seal is between 65 and 95 Shore A.

In one embodiment of the invention, the sealing means includes a deformable seal sandwiched between the primer housing and the deflector, the seal having a central passage in register with the central aperture of the deflector.

The cartridge case may include protection means for in use protecting a primer, such as a percussion cap, seated in the primer housing against the pressurized gas, thereby to prevent the primer from being unseated by the pressurized gas.

The protection means may include a displaceable plug body located in front of a flash hole outlet of the primer housing, the plug body being displaceable between a first position in which the flash hole of the primer housing is unobstructed, and a second position in which the plug body obstructs the flash hole outlet of the primer housing.

In one embodiment of the invention, the protection means includes a displaceable plug body located in the central passage of the seal, the plug body being displaceable between a first position in which the flash hole of the primer housing is unobstructed, and a second position in which the plug body obstructs the flash hole of the primer housing .

The central passage of the cartridge case may be circular cylindrical and may have a constant diameter along its length, at least above the primer housing. Instead, the cartridge case may have a shoulder, typically tapered at 1 5 °, to steer propellant forces to the center of a projectile mounted to it, and to relieve a remaining neck portion of the case of stresses. An undercut may be provided at the primer mounting end of the cartridge case. The undercut may provide a seating surface for the deflector.

The cartridge case may be of material conventionally used for cartridge cases, or it may be of a material selected specifically for its ability to handle pressures higher than that of conventional cartridges of the same caliber. Examples of materials for the cartridge case are stainless steel 304, 31 6, 321 , 310, nylon with memory capabilities, nickel or chrome plated carbon steels, brass, bronze and aluminium bronze. The cartridge case may be pressed, drop forged, machined or injection molded .

In one embodiment of the invention, the primer housing is of aluminium and the cartridge case is of a synthetic plastics or polymeric material, such as nylon, which may be injection molded.

According to a third aspect of the invention, there is provided protection means for in use protecting a primer of a cartridge against pressure produced inside a case of the cartridge by a combusted propellant, the protection means including a plug body which is dimensioned to fit inside the case of the cartridge and which defines a plug for plugging a flash hole of the cartridge.

The plug body may define at least one passage for a flash produced by a primer to travel through. The plug body may thus be in the form of a disc having at least one aperture or passage or having at least one peripheral portion removed therefrom, a central area of the disc being continuous and free of apertures to provide a seal or plug for the flash hole or passage when the disc is in its second position. Preferably, the combined cross sectional area of the apertures or passages of the plug body is larger than the cross sectional area of the flash hole intended to be plugged by the plug body. The plug body may be dimensioned to fit snugly inside the cartridge case, or, in some embodiments, inside the central passage of the seal.

The thickness of the plug body is dependent on the pressure it would be required to withstand without deforming appreciably, and can be determined by routine experimentation. The plug body may be of a solid metal or a solid synthetic plastics or polymeric material such as nylon.

According to a fourth aspect of the invention, there is provided a cartridge which includes an elongate cartridge case which houses propellant; a primer for the propellant located at a primer mounting end of the cartridge case; and a projectile as hereinbefore described removably mounted to a projectile mounting end of the cartridge case, at least a portion of the projecting mounting formation of the projectile extending into the cartridge case.

The cartridge case may be as hereinbefore described.

The mounting formation may be of an alloy, the projectile body may be of nylon, the cartridge case may be of nylon, and the primer housing may be of aluminium. In one embodiment of the invention, the projectile body is of nylon 6 and the cartridge case is of nylon 66. Nylon components may be injection molded or machined from nylon rods.

The cartridge case may have a neck which has an increased wall thickness compared to a conventional cartridge case of the same caliber. Similarly, if desired, a body portion of the cartridge case extending between the ends may have an increased wall thickness compared to a conventional cartridge case of the same caliber. The cartridge may thus include a propellant producing higher pressures than the pressures produced by the propellant of conventional cartridges of the same caliber, thus advantageously leading to a higher muzzle velocity for the projectile in use.

Duplex or triplex load may be used as propellant. With a nylon projectile body, the projectile will have a very low coefficient of friction, and the propellant should thus be as fast burning as possible. A combination of fast burning propellant and medium burning propellant is expected to be suitable.

The cartridge may safely produce a pressure in the cartridge case in excess of CIP standard pressures, without cartridge case head separation or cracking of the cartridge case occuring. However, it is preferable to remain within the CIP limits.

Typically, the projectile body and the cartridge case abut in a planar annular face to planar annular face relationship. The base of the projectile body and a leading surface of the cartridge case are thus typically planar. If desired, the projectile body may have a beveled trailing end, or may be tapered. In other words, if desired, the projectile body may have a so-called boat tail. The invention extends to a cartridge which includes protection means for in use protecting a primer of the cartridge against pressure produced inside a case of the cartridge by a combusted propellant.

The protection means may be as hereinbefore described .

It is expected that the projectile, cartridge case, cartridge and protection means of the invention will be particularly, though not necessarily exclusively, suitable for handheld firearms having relatively small bores such as pistols, revolvers, hunting rifles and military rifles, machine guns and the like.

The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which

Figure 1 shows a longitudinally sectioned exploded side view of a cartridge in accordance with the invention;

Figure 2 shows a longitudinally sectioned exploded side view of another embodiment of a cartridge in accordance with the invention, which includes protection means for a primer;

Figure 3 shows a longitudinally sectioned exploded side view of a further embodiment of a cartridge in accordance with the invention;

Figure 4 shows a longitudinally sectioned side view of yet a further embodiment of a cartridge in accordance with the invention;

Figure 5 shows a longitudinally sectioned side view of yet another embodiment of a cartridge in accordance with the invention;

Figure 6 shows a top plan view of protection means in accordance with the invention for a primer; Figure 7 shows a top plan view of another embodiment of protection means in accordance with the invention for a primer;

Figure 8 shows a top plan view of a further embodiment of protection means in accordance with the invention for a primer;

Figure 9 shows a partially sectioned side view of a projectile in accordance with the invention; Figure 1 0 shows a sectioned side view of a further embodiment of protection means in accordance with the invention for a primer;

Figure 1 1 shows a sectioned side view of yet a further embodiment of protection means in accordance with the invention for a primer; Figure 1 2 shows a longitudinally partially sectioned exploded three dimensional view of yet a further embodiment of a cartridge in accordance with the invention; and

Figure 1 3 shows a longitudinally partially sectioned side view of the assembled cartridge of Figure 1 2.

Referring to Figure 1 of the drawings, reference numeral 1 0 generally indicates a cartridge in accordance with the invention, which is suitable for use with a rifle.

The cartridge 1 0 includes a cartridge case 1 2 for propellant (not shown) and a projectile comprising an elongate projectile body or bullet 14 mounted to the cartridge case 1 2 by means of a mounting formation, in the form of an elongate insert 7 projecting from a base or rear or trailing end 21 of the projectile body 14 into a circular cylindrical bore 20 of the cartridge case 1 2. The base 21 is planar and annular. The cartridge 1 0 also includes a primer, in the form of a percussion cap 22 which is seated in a base 24 of the cartridge case 1 2. A flash hole or passage 26 extends between the percussion cap 22 and the bore 20.

The insert 7 is circular cylindrical and has a diameter at least half the diameter of the projectile body 14, which is circular in end view. The insert 7 thus has a smaller maximum transverse dimension than the projectile body 14. The insert 7 extends into the projectile body 14, with about two thirds of the length of the insert 7 being located frictionally inside a blind-ended passage in the projectile body 14 and one third of the insert 7 projecting from the base 21 of the projectile body 14. The insert 7 is of stainless steel and is coaxial with the projectile body 14, which is of copper. The cartridge case 1 2 has a planar annular leading surface 28. The projectile body 1 4 and the cartridge case 1 2 thus abut in a planar face to planar face relationship, the planar annular base 21 seating against the planar leading surface 28.

As can be seen in Figure 1 , the cartridge case 1 2 has a neck

30 which has an increased wall thickness compared to a conventional cartridge case of the same caliber. Similarly, a body portion 32 of the cartridge case 1 2 has an increased wall thickness compared to a conventional cartridge case of the same caliber. The wall thickness is substantially constant over the length of the cartridge case 1 2, the bore 20 widening in a transitional or shoulder region 34 between the neck 30 and the body portion 32.

The bore 20 is dimensioned in the region of the neck 30 such that the insert 7 fits snugly with a friction fit into the bore 20. An end 36 of the insert 7 remote from the projectile body 14 is beveled to facilitate insertion of the insert 7 into the bore 20. The bore 20 is coaxial with the projectile body 14 and the insert 7.

Referring to Figure 2 of the drawings, another embodiment of a cartridge in accordance with the invention is generally indicated by reference numeral 50. The cartridge 50 is similar to the cartridge 1 0 and, unless otherwise indicated, the same reference numerals used above are used to indicate the same or similar parts or features.

The insert 7 extends coaxially through the projectile body 1 4, defining a nose 52 for the projectile body 14. The cartridge 50 also includes retaining means, in the form of a circlip 54, which inhibits removal of the insert 7 from the projectile body 14. Unlike the bore of the cartridge 10, the bore 20 of the cartridge 50 has a constant diameter. The cartridge 50 includes protection means 100, which is discussed in more detail below, for in use protecting the percussion cap 22 from the pressure produced by the propellant, thus preventing the percussion cap 22 from being unseated or blown out of the base 24 of the cartridge case 1 2 when the cartridge 50 is fired .

Referring to Figure 3 of the drawings, a further embodiment of a cartridge in accordance with the invention is generally indicated by reference numeral 60. The cartridge 60 is similar to the cartridge 10, 50, and unless otherwise indicated, the same reference numerals used above are used to indicate the same or similar parts or features.

The projectile body 1 4 has a beveled trailing end. Thus, the projectile body 14 has a so-called boat tail. As can be seen in Figure 3, the insert 7 has a larger portion thereof extending into the projectile body 1 4, than is the case with the insert 7 of the cartridge 10.

Referring to Figures 4 and 5 of the drawings, yet further embodiments of a cartridge in accordance with the invention are generally indicated by reference numerals 70 and 80 respectively. The cartridge 70,

80 is similar to the cartridge 10, 50, 60 and, unless otherwise indicated, the same reference numerals used above are used to indicate the same or similar parts or features.

Unlike the cartridge 10, 50, 60, the cartridge 70 includes a mounting formation 72 which is integral with the projectile body 14.

Unlike the cartridge 1 0, 50, 60, 70, the cartridge 80 is of a caliber and size making it suitable for use with a hand gun.

When the cartridge 10, 50, 60, 70, 80 is fired from a firearm, the projectile body or bullet 14 is driven away from the cartridge case 1 2 by means of the pressure produced inside the cartridge case 1 2 by the propellant acting on the free end 36 of the insert 7 or mounting formation

72, as the case may be. The insert 7 or mounting formation 72 is pushed out of the bore 20 of the cartridge case 1 2, and travels together with the projectile body 1 4 down the barrel of the firearm.

Referring to Figure 6 of the drawings, reference numeral 100 generally indicates protection means for in use protecting a primer, such as a percussion cap, seated in a cartridge case, from the pressure produced by the propellant inside the cartridge case.

The protection means 100 includes a metal body 102 which is disc-shaped in side view (not shown) and which has four semi-circular portions removed therefrom, leaving the body 102 with four equiangularly spaced semi-circular recesses or channels 104 in a periphery thereof.

Referring to Figures 7 and 8, two further embodiments of protection means in accordance with the invention are generally indicated by reference numerals 1 1 0 and 1 20 respectively. The protection means 1 1 0 and 1 20 are similar to the protection means 1 00 and the same reference numerals are used to indicate the same or similar parts or features.

In the case of the protection means 1 1 0, four radially extending rectangular slots or passages 1 1 2 are provided through the body 102. In the case of the protection means 1 20, four circular apertures or passages, arranged in a square, are provided through the body 102.

As will be noticed, in each of the protection means 100, 1 1 0 and 1 20, a central area 1 06 of the body 102 is continuous and free of apertures.

In use, the protection means 1 00 is located between a propellant (not shown) in the bore 20 of the cartridge 50 and the base 24 of the cartridge case 1 2. The central area 106 of the body 102 provides a plug or seal for the flash hole or passage 26 when the protection means 1 00 is located in face to face abutting relationship with the base 24 of the cartridge case 1 2. When the cartridge 50 is fired, the protection means 1 00 is displaced slightly away from the base 24 owing to the increased pressure in the flash hole or passage 26 caused by the firing of the percussion cap 22. The flash produced by the percussion cap 22 can thus travel over the central area 106 of the body 1 02 and through the recesses 1 04, to ignite the propellant. When the propellant ignites, the protection means 1 00 is forced rearwardly against the base 24 of the cartridge case 1 2 owing to the increased pressure in the bore 20, thus again sealing or blocking off the flash hole or passage 26, protecting the percussion cap 22 against the pressure produced by the propellant inside the bore 20, thus ensuring that the percussion cap 22 is not unseated or blown out of the base 24.

The protection means 1 1 0, 1 20 function in the same fashion as the protection means 100.

Referring to Figure 9 of the drawings, a projectile in accordance with the invention is generally indicated by reference numeral 1 30. The projectile 1 30 also comprises a projectile body 14 and an insert 7, similar to the projectiles of the cartridges 10 et al already discussed, and unless otherwise indicated, the same reference numerals are used to indicate the same or similar parts or features.

The projectile body 14 is of nylon 6 and is injection molded over the insert 7, which is of a solid metal alloy. The ratio of the maximum diameter of the insert 7, which is circular in cross section, to the maximum diameter of the projectile body 14, which is circular in outline in end view, is about 0,79: 1 . The insert 7 defines a retaining formation in the form of a splined cannelure 1 32. The projectile body 14 is molded into the cannelure 1 32, thus defining a complimentary retaining formation to secure the projectile body 1 4 to the insert 7. A rear or trailing surface of the end 36 of the insert 7 is concavely curved or inwardly domed, thereby in use directing or concentrating the force produced by combusting propellant inside a cartridge case towards a central longitudinal axis (not shown) of the projectile 1 30, and enhancing the creation of a vacuum behind the insert 7 during flight of the projectile 1 30, thus promoting the stability of the projectile 1 30. The insert 7 is configured to mount the projectile body 14 with a friction fit to a cartridge case. The insert 7 tapers slightly toward its end 36 to facilitate insertion thereof into a cartridge case, and define an annular recess 1 34 adjacent the projectile body 14 for engaging a complimentary annular retaining protrusion defined by a cartridge case.

Referring to Figures 10 and 1 1 of the drawings, reference numerals 1 40 and 1 50 generally indicate further embodiments of protection means for in use protecting a primer, such as a percussion cap, seated in a cartridge case or a primer housing, from the pressure produced by the propellant inside the cartridge case. The protection means 140 and 1 50 each respectively includes an integrally molded plug body 142 and 1 52. The plug bodies 142, 1 52 are circular in outline in plan view (not shown) and are dimensioned to fit inside the case of a cartridge, either inside the case per se or inside a central aperture of a seal located inside the case, as discussed in more detail below. Each plug body 142, 1 52 defines a plug 144, 1 54 respectively for sealing or plugging a flash hole or passage of a cartridge. Each plug body 1 42, 1 52 also defines passages 146, 1 56 respectively for a flash produced by a primer to travel through.

Referring now to Figures 1 2 and 1 3 of the drawings, reference numeral 200 generally indicates a cartridge in accordance with the invention. The cartridge 200 includes the projectile 1 30, and a cartridge case 202 which comprises a primer housing 204 and sealing means 206 for inhibiting escape of pressurized gas, in use produced by combusted propellant (not shown) inside the cartridge case 202 between an interior surface 208 of the cartridge case 202 and the primer housing 204. The cartridge case 202 is of nylon 66 and is elongate with a central passage or bore 21 0 extending therethrough. The case 202 is open at both a projectile mounting end 21 2 and a primer mounting end 214. The projectile 1 30 is mounted by means of its insert 7 with a friction fit to the projectile mounting end 21 2 of the cartridge case 202. The cartridge case

202 defines an annular retaining protrusion 21 6 which engages the annular recess 1 34 of the insert 7. At the primer mounting end 214 of the cartridge case 202, an undercut 21 8 is defined which is slightly larger than the bore 21 0 extending way from the undercut 21 8. The length of the undercut is about 1 0 mm (for rifle calibers 308, 303 30-06 or the like) . The cartridge case 202 also has a shoulder 220 and a neck 222. The shoulder tapers at an angle of 1 5 ° towards the neck 222. At the primer mounting end 21 4 of the cartridge case 202, the cartridge case 202 defines a plurality of annular serrations or corrugations 224, covering a lower portion of the undercut 21 8.

The cartridge case 202 is injection molded from nylon 66. It is also expected that the cartridge case 202 and projectile body 1 14 can be molded simultaneously around the insert 7. After having been removed from the mold, the case 202 is boiled or annealed in water for about 5 hours, to ensure that the case 202 can expand under the pressure produced internally during firing of the cartridge 200, without cracking. Before assembly of the cartridge 200, the cartridge case 202 should be rested for about 24 hours to return to its original molded size. As will be appreciated by those skilled in the art, different annealing procedures will be required for different materials for the cartridge case.

For its low mass and ease of machining or pressing, the primer housing 204 is of aluminium and comprises a substantially cylindrical portion 226 which defines a plurality of annular serrations or corrugations 228 which cooperate with the corrugations 224 of the cartridge case 202 when the cylindrical portion 226 is clipped into the undercut 21 8. This is clearly illustrated in Figure 1 3 of the drawings. The primer housing 204 defines a seat 230 for a percussion cap 232 and a flash hole or passage 235. An ejector rim (not shown) is provided in a base of the primer housing 204. A circular recess 237 is provided in a free end of the cylindrical portion 226.

The sealing means 206 includes a deflector 234 for in use inwardly deflecting pressurized gas moving towards the primer mounting end 214 away from the interior surface 208 towards a central longitudinal axis (not shown) of the cartridge case 202. The deflector 234 has a deformable body of nylon 6 which defines an inverted frusto-conical deflection surface 236. The angle of the deflection surface 236 relative to the central longitudinal axis of the cartridge case 202 is about 60° . A central aperture 238 is provided in the body of the deflector 234. The deflector 234 is pressed into the undercut 21 8 and an annular seating surface 240 of the deflector 234 seats against an annular top of the undercut 21 8, as is clearly illustrated in Figure 1 3 of the drawings. A circular recess 242 is provided in a bottom of the body of the deflector 234.

The sealing means 206 also includes a deformable seal 244 sandwiched snugly between the deflector 234 and the primer housing 204. The seal 244 has a central passage 246 in register with the aperture 238 and the flash hole 235. Cylindrical stub-like portions 248 and 250 of the seal 244 each respectively fits into the recess 242 of the deflector 234 and the recess 237 of the primer housing 204.

The plug body 142 of the protection means 140 is located in the passage 246 of the seal 244 such that the plug body 142 can be displaced in the passage 246, at least towards the primer housing 204. The plug body 142 fits snugly inside the passage 246 (not shown in Figure 1 2) . The cartridge case 202 can be loaded with propellant either from its projectile mounting end 21 2 or its primer mounting end 214, depending on whether the primer housing 204 and sealing means 206, or the projectile 1 30 is fitted first.

Once assembled, the cartridge 200 can be soaked in a water repellant oil additive such as "Prolong " or the like.

When fired in use in a rifle, the percussion cap 232 of the cartridge 200 produces a flash in conventional manner. The flash moves through the flash hole 235 , the passage 246 and the passages 146, and the aperture 238 and ignites the propellant in the cartridge case 202. The combusting propellant produces pressurized gas which acts on the end 236 of the insert 7 and drives the insert 7 and projectile body 14 through the barrel of the rifle.

The pressurized gas also moves towards the primer mounting end 214 of the cartridge case 202. The deflector 234 deflects the gas towards the central aperture 238, whilst at the same time being deformed by the gas and forced against the interior surface 208 of the cartridge case 202, thus also performing a sealing function. The pressurized gas enters the passage 246 of the seal 244 and expands the seal 244 radially outwardly against the interior surface 208 of the cartridge case 202. The seal 244 thus inhibits escape of gas between the cartridge case 202 and the primer housing 204.

The pressurized gas also forces the plug body 142 towards the flash hole 235 so that the plug 144 plugs the flash hole 235, thus protecting the primer 232 from the pressurized gas.

The cartridge 10 e a/, as illustrated, each has at least some of the following advantages, depending on the particular configuration of the cartridge: propellants generating higher pressures may be used owing to the increased wall thickness of the cartridge case; the cartridge case may handle high pressures and temperatures without any significant change in shape, accordingly increasing the life of the cartridge case; in some cases, less propellant may be used without a sacrifice in the pressure developed by the propellant inside the cartridge case; sound engineering practices such as dropforging, pressing and machining can be used to manufacture the cartridge case; - the weight and energy of the projectile is more controllable and less material may be used in the manufacturing of the projectile. If desired, projectiles can be provided having the same dimensions as a conventional projectile, but having an increased weight; cartridge case head separation and cracking of the cartridge case can be eliminated or at least substantially reduced; projectiles with an increased velocity and less dependency on overhold at increased ranges can be provided. At very high projectile velocities, the barrel of the firearm would not have to be rifled; reloading of the cartridge is easy since bullet seating depth is predetermined by the length of the mounting formation projecting from the base of the projectile, and thus the length of the cartridge remains constant. The projectile is also perfectly aligned with the cartridge case; the cartridge can be fired from existing firearms without any modifications thereto; - the use of lead in the projectile can be eliminated or at least reduced; the cartridge allows a number of different materials to be used with greater ease for the production of the cartridge than conventional cartridges, providing a light cartridge which is corrosion resistant. - the greater wall thickness of the cartridge case, especially in the neck region of the cartridge case provides for a safer cartridge, while at the same time providing the ability to handle higher pressures and produce increased velocities and greater accuracy; the cartridge can lead to less rifle kick; the barrel of a firearm firing the cartridge will run colder, providing consistent accuracy; the use of nylon is cost effective; - uniform parts can be used over a wide range of calibers; the components are produced with consistent accuracy by injection molding the cartridges, causing less wear of rifle parts; barrel fouling is reduced with the use of a nylon projectile body and the bore of the rifle is coated after every shot; - the bore of the cartridge can remain standard over a wide range of calibers; the cartridge can be assembled without complex tools or dies; a military version of the cartridge can be saboted; the mounting formation or insert can be hardened in oil which will generate high temperatures in flight; the projectile can be configured to break up under impact; and minor deviations in propellant weight are not critical.

Claims

CLAIMS:

1 . A projectile for a cartridge, the projectile including a projectile body and mounting means for removably mounting the projectile body to a cartridge case, the mounting means including a mounting formation which projects from a base of the projectile body and which has a smaller maximum transverse dimension than a maximum transverse dimension of the projectile body.

2. A projectile as claimed in claim 1 , in which the projectile body is elongate and circular in outline in end view and the mounting formation is elongate and circular in cross section, thus having a maximum diameter which is smaller than the maximum diameter of the projectile body.

3. A projectile as claimed in claim 1 or claim 2, in which the maximum transverse dimension of the mounting formation is at least half the maximum transverse dimension of the projectile body, but smaller than that of the projectile body by a sufficient margin to ensure that the mounting formation does not interfere with the rifling of a barrel when the projectile body is fired through a rifled barrel dimensioned in conventional manner for the caliber of the projectile.

4. A projectile as claimed in any one of the preceding claims, in which a ratio of the maximum transverse dimension of the mounting formation to the maximum transverse dimension of the projectile body is between 0,5: 1 and 0,95: 1 .

5. A projectile as claimed in claim 4, in which the ratio of the maximum transverse dimension of the mounting formation to the maximum transverse dimension of the projectile body is between 0,75: 1 and 0,95: 1 .

6. A projectile as claimed in any one of the preceding claims, in which the mounting formation is integral with the projectile body.

7. A projectile as claimed in any one of claims 1 to 5 inclusive, in which the mounting formation is a separate body attached to the projectile body.

8. A projectile as claimed in claim 7, in which the mounting formation is in the form of an insert which extends into the projectile body and which projects away from a rear end of the projectile body.

9. A projectile as claimed in claim 8, in which the insert defines a retaining formation cooperating with a complimentary retaining formation defined by the projectile body, thereby to secure the projectile body to the insert.

10. A projectile as claimed in claim 9, in which the retaining formation defined by the insert includes a cannelure.

1 1 . A projectile as claimed in claim 10, in which the cannelure includes at least one angled spline.

1 2. A projectile as claimed in any one of the preceding claims, in which the mounting formation is of a material selected from the group consisting of solid metals, alloys, ceramics, and solid synthetic plastics or polymeric materials.

1 3. A projectile as claimed in claim 1 2, in which the mounting formation is of a solid synthetic plastics or polymeric material.

14. A projectile as claimed in any one of the preceding claims, in which the projectile body is of a material selected from the group consisting of solid metals, alloys, and solid synthetic plastics or polymeric materials.

1 5. A projectile as claimed in claim 14, in which the projectile body is of a solid synthetic plastics or polymeric material.

1 6. A projectile as claimed in any one of the preceding claims, in which a rear surface of the mounting formation, remote from the projectile body, is concavely curved.

1 7. A projectile as claimed in any one of the preceding claims, in which the projecting portion of the mounting formation is shaped to enhance a friction fit between the mounting formation and a cartridge case.

1 8. A cartridge case which is elongate with a central passage extending therethrough and which is open at both a projectile mounting end for mounting a projectile to the cartridge case such that it projects from the cartridge case, and a primer mounting end, a primer housing for housing a primer being fitted to the primer mounting end of the cartridge case.

1 9. A cartridge case as claimed in claim 1 8, in which the primer housing has a substantially cylindrical portion fitting with a friction fit into the primer mounting end of the cartridge case.

20. A cartridge case as claimed in claim 1 8 or claim 1 9, which includes sealing means for inhibiting escape of pressurized gas, in use produced by combusted propellant inside the cartridge case, from the cartridge case between an interior surface of the cartridge case and the primer housing.

21 . A cartridge case as claimed in claim 20, in which the sealing means includes a deflector for in use inwardly deflecting pressurized gas moving towards the primer mounting end of the cartridge case away from the interior surface of the cartridge case towards a central longitudinal axis of the cartridge case.

22. A cartridge case as claimed in claim 21 , in which the deflector has a central aperture and is deformable such that in use it is deformed against the interior surface of the cartridge case by the pressurized gas.

23. A cartridge case as claimed in any one of claims 20 to 22 inclusive, in which the sealing means includes a deformable seal abutting against the primer housing and located inside the cartridge case, the seal having a central passage and being arranged such that in use it is forced against the primer housing and the interior surface of the cartridge case by the pressurized gas.

24. A cartridge case as claimed in claim 22, in which the sealing means includes a deformable seal sandwiched between the primer housing and the deflector, the seal having a central passage in register with the central aperture of the deflector.

25. A cartridge case as claimed in claim 22, which includes protection means for in use protecting a primer seated in the primer housing against the pressurized gas, thereby to prevent the primer from being unseated by the pressurized gas.

26. A cartridge case as claimed in claim 24, in which the protection means includes a displaceable plug body located in the central passage of the seal, the plug body being displaceable between a first position in which a flash hole of the primer housing is unobstructed, and a second position in which the plug body obstructs the flash hole of the primer housing.

27. A cartridge case as claimed in any one of claims 1 8 to 24 inclusive, which includes protection means for in use protecting a primer seated in the primer housing against the pressurized gas, thereby to prevent the primer from being unseated by the pressurized gas.

28. A cartridge case as claimed in claim 27, in which the protection means includes a displaceable plug body located in front of a flash hole outlet of the primer housing, the plug body being displaceable between a first position in which the flash hole of the primer housing is unobstructed, and a second position in which the plug body obstructs the flash hole outlet of the primer housing.

29. A cartridge case as claimed in any one of claims 1 8 to 28 inclusive, in which the central passage of the cartridge case is circular cylindrical and has a constant diameter along its length, at least above the primer housing.

30. A cartridge case as claimed in any one of claims 1 8 to 29 inclusive, in which the primer housing is of aluminium and the cartridge case is of a synthetic plastics or polymeric material.

31 . Protection means for in use protecting a primer of a cartridge against pressure produced inside a case of the cartridge by a combusted propellant, the protection means including a plug body which is dimensioned to fit inside the case of the cartridge and which defines a plug for plugging a flash hole of the cartridge.

32. Protection means as claimed in claim 31 , in which the plug body defines at least one passage for a flash produced by a primer to travel through.

33. A cartridge which includes an elongate cartridge case which houses propellant; a primer for the propellant located at a primer mounting end of the cartridge case; and a projectile as claimed in any one of claims 1 to 1 7 inclusive removably mounted to a projectile mounting end of the cartridge case, at least a portion of the projecting mounting formation of the projectile extending into the cartridge case.

34. A cartridge as claimed in claim 33, in which the cartridge case is as claimed in any one of claims 1 8 to 30 inclusive.

35. A cartridge as claimed in claim 34, in which the mounting formation is of an alloy, the projectile body is of nylon, the cartridge case is of nylon, and the primer housing is of aluminium.

36. A cartridge as claimed in claim 34 or claim 35, in which the projectile body is of nylon 6 and the cartridge case is of nylon 66.

37. A cartridge which includes protection means for in use protecting a primer of the cartridge against pressure produced inside a case of the cartridge by a combusted propellant.

38. A cartridge as claimed in claim 37, in which the protection means is as claimed in claim 31 or claim 32.

39. A projectile as claimed in claim 1 , substantially as herein described and illustrated.

40. A cartridge case as claimed in claim 1 8, substantially as herein described and illustrated.

41 . Protection means as claimed in claim 31 , substantially as herein described and illustrated.

42. A cartridge as claimed in claim 33 or claim 37 substantially as herein described and illustrated.

43. A new projectile for a cartridge; a new cartridge case; a new protection means for in use protecting a primer of a cartridge against pressure produced inside a case of the cartridge by a combusted propellant; or a new cartridge, substantially as herein described.