Ammunition cartridge

Abstract

Ammunition cartridge comprising a casing (4), a propellant charge (10) contained inside the casing, an ignition device (8), and a projectile (6), the casing (4) including a base (14), a tubular sleeve (16), and a projectile holding section (3), the base (14) closing a first end of the casing and the projectile holding section forming a second end of the casing configured to hold the projectile (6) mounted at said second end of the casing, the projectile holding section (3) having a first holding part (3a) forming a tubular outer extension portion (24) extending axially forwardly from a conical transition portion (23) of the tubular sleeve (16) and configured to grip a center body section (22) of the projectile (6). The projectile holding section (3) further comprises a second holding part (3b) including a tubular inner extension portion (5) extending axially rearwardly and configured to grip the center body section (22) of the projectile.

Description

[0001] Ammunition Cartridge

[0002] Field of the Invention

[0003] This invention relates to an ammunition cartridge, in particular for rifles and firearms.

[0004] Background of the Invention

[0005] Conventional ammunition cartridges for firearms and guns of various sizes and purposes typically comprise a deep drawn brass or steel casing containing a propellant charge in the form of powder or granules of a combustible substance, and a projectile assembled in a gripping fit at an open tubular sleeve end of the casing. Most projectiles are massive, cylindrical objects with an aerodynamic tip at the front and a flared shape with a flat base at the rear. The latter is usually mounted inside the cartridge casing whereas the aerodynamical tip is outside the cartridge casing.

[0006] All cartridges have dimensions that are specified by the corresponding firearm. More specifically, the cartridge case dimensions must match the firearm combustion chamber within tight tolerances because the pressure produced by the propellant’s combustion is so high that without the physical limits set by the thick-walled combustion chamber, the cartridge casing would tear apart.

[0007] In conventional ammunition cartridges it is not possible to substantially increase the length of the projectile, and in particular the leading (forward) portion of the projectile. The portion of the projectile extending out of the open tubular sleeve end of the casing is limited dimensionally by the inner dimensions of the breech and barrel, and the portion within the cartridge is limited in length by the dimensions of the casing. This is because the length of the tubular sleeve end of the casing that grips the projectile affects the stability and angular positional accuracy of the projectile. In addition, the overall length of the cartridge, from the case basis to the projectile tip is set by the weapon’s magazine. An increase in length of the profiled leading portion of the projectile would push backwards its cylindrical part, the projectile section that matches the case mouthing and is used for gripping solidly the projectile and the cartridge case, reducing the length of the portion of sleeve gripping the projectile. More generally, increasing the overall length of the projective relative to the length of the gripping sleeve end of the projectile, reduces the holding stability and accuracy of the projectile.

[0008] These constraints limit the dimensions and shape of the projectile. The dimensions and shape of a projectile however affect its aerodynamical behavior, and as a consequence both the accuracy of flight and the range of the projectile. In particular, longer projectiles, with longer leading tip profiles, can be designed to offer better aerodynamic performance than shorter projectiles. Their lower energy loss along the flight path and as a consequence their higher remaining energy increase substantially their impact potential.

[0009] It is consequently desirable in many applications to increase the length of the projectile in order to improve its range limit, its flight accuracy and its impact potential.

[0010] Summary of the Invention

[0011] In view of the foregoing, it is an object of the invention to provide an ammunition cartridge with improved performance, in particular improved projectile flight accuracy and range.

[0012] It is advantageous to provide an ammunition cartridge that is economical to manufacture in large quantities.

[0013] It is advantageous to provide improved ammunition cartridges that can be used in existing weapons, in particular ammunition cartridges that have outer dimensions conform to standard widespread cartridge sizes.

[0014] Objects of this invention have been achieved by providing the ammunition cartridge according to claim 1 . Dependent claims recite various advantageous features or variants.

[0015] Disclosed herein, is an ammunition cartridge comprising a casing, a propellant charge contained inside the casing, an ignition device, and a projectile, the casing including a base, a tubular sleeve including a container portion and a conical transition portion, and a projectile holding section, the base closing a first end of the casing and the projectile holding section forming a second end of the casing configured to hold the projectile mounted at said second end of the casing.

[0016] The projectile holding section comprises a tubular inner extension portion extending axially rearwardly and configured to grip the center body section of the projectile.

[0017] According to a first aspect of the invention, the projectile holding section has a first holding part forming a tubular outer extension portion extending axially forwardly from the conical transition portion of the tubular sleeve and configured to grip a center body section of the projectile, and a second holding part including at least said tubular inner extension portion, the projectile holding section comprising a separately formed part fixed to the tubular sleeve of the casing by a weld connection, said separate part including at least said tubular inner extension portion. In an embodiment the first holding part is integrally formed with the tubular sleeve of the casing.

[0018] In an advantageous embodiment of the first aspect, the separately formed projectile holding section comprises the tubular outer extension portion, the tubular inner extension portion and the fixing cone portion.

[0019] According to a second aspect of the invention, the projectile holding section comprises a separately formed part, said separate part including at least said tubular inner extension portion and a fixing cone portion welded to the conical transition portion of the tubular sleeve.

[0020] In an advantageous embodiment, the fixing cone portion is mounted against an inner side of the conical transition portion, the inner side facing an inside of the container portion.

[0021] In an advantageous embodiment, the base and tubular sleeve are made of stainless steel.

[0022] In an advantageous embodiment, the base of the casing is separately formed from the tubular sleeve and attached thereto by welding or crimping.

[0023] In an advantageous embodiment, the base and tubular sleeve of the casing are integrally formed as a single piece.

[0024] In an advantageous embodiment, a length of the projectile second holding part is in a range of 0.2 to 0.5 of an overall length of the projectile holding section.

[0025] In an advantageous embodiment, the tubular inner extension portion of the projectile holding section comprises venting holes line configured to allow combustion gas and unburned propellant particles to pass through the tubular inner extension portion.

[0026] Further objects and advantageous features of the invention will be apparent from the claims, and from the following detailed description and accompanying figures.

[0027] Brief Description of the drawings

[0028] The invention will now be described with reference to the accompanying drawings, which by way of example illustrate embodiments of the present invention and in which:

[0029] Figure 1a is a schematic cross-sectional view of an ammunition cartridge according to a first embodiment of the invention; Figure 1b is a perspective view of a projectile holding section of the ammunition cartridge according to the first embodiment;

[0030] Figure 1c is a cross sectional view of the projectile holding section of figure 1 b;

[0031] Figure 2a is a schematic cross-sectional view of an ammunition cartridge according to a second embodiment of the invention;

[0032] Figure 2b is a cross sectional view of a projectile holding section of the ammunition cartridge according to the second embodiment;

[0033] Figure 3 is an illustration of various conventional common caliber cartridges, showing the length of the cartridges.

[0034] Detailed description of embodiments of the invention

[0035] Referring to the figures, an ammunition cartridge 2 comprises a casing 4, a projectile 6, an ignition device 8, and a propellant charge 10. The projectile 6 may be made of various materials that are perse known in the field of ammunition cartridges and has a waist diameter Dp defining a caliber configured for a barrel of a weapon. The casing diameter De and length Lc are dependent on the loading chamber of the weapon and cartridge magazine it is intended for use with. The ammunition cartridge outer shape and dimensions may advantageously be configured to conform to a standard size for use with existing firearms and rifles, in replacement of existing ammunition cartridges.

[0036] The present invention is in particular well adapted for long ammunition used for rifles, for instance ammunition types as illustrated in figure 4. Ammunition cartridges according to embodiments of this invention may in particular have a caliber in a range of 5mm to 9mm and an overall length in a range from 40mm to 80mm. The ratio of length to maximum diameter of the casing for such ammunition is in a range of 4.5 to 7 (four and a half to seven), preferably in a range of 5 to 7 (five to seven). The present invention is however also applicable to larger caliber ammunitions, namely the medium caliber ammunitions ranging typically from 15 to 40 mm, used in cannons.

[0037] The casing 4 generally has a cylindrically shaped tubular sleeve 16 closed at one end by a base 14 lodging an ignition device 8. At the other end of the casing, the projectile 6 is attached in a grip fit to a projectile holding section 3 of the casing. The projectile holding section 3 comprises a tubular outer extension portion 24 connected via a tapered portion 23 to a major portion 25 of the tubular sleeve 16 containing the propellant charge 10, the tubular outer extension portion 24 having a smaller diameter than the major portion 25. The outer shape of the base 14 may have various configurations depending on the weapon with which it is intended to be used, and may for instance typically comprise a rim 27 and annular groove 29 that serve to eject the casing from the firing chamber of the weapon as is perse well-known in the art.

[0038] In a second embodiment, the casing 4 may be made of a single piece part, namely formed from a single piece of material such as a conventional brass ammunition casing, for instance as illustrated in figures 1 and 2.

[0039] In certain embodiments, the base 14 and tubular sleeve 16 of the casing may be assembled from two or more parts, as illustrated in the embodiments of figures 1 a and 3. The tubular sleeve 16 and the base 14 are preferably assembled together by welding, although in variants they may alternatively or in addition be assembled by crimping. The separate base 14 and tubular sleeve 16 allows assembly of the propellant charge 10 into the casing tubular sleeve from the base end 31 before assembly of the base 14 to the tubular sleeve 16. In these embodiments, the propellant charge may also be assembled in a conventional manner from the open neck end 33 once the multi-part casing is assembled.

[0040] In embodiments where the base 14 and tubular sleeve 16 are assembled from two or more parts, as illustrated in figure 1a, the casing is preferably made of steel, whereby the tubular sleeve 16 may be made from sheet metal, rolled into a tube and welded along an axial seam. The tubular sleeve may also be extruded. The tubular sleeve is preferably welded to the stainless steel base 14.

[0041] . It may be noted that the embodiments of both figures 1a-1c and 2a-b may also be made of a polymer or composite material.

[0042] In the embodiment of figures 2a-b, the base 14 and tubular sleeve 16 may be made for instance of brass, or stainless steel, in a manner similar to conventional casings using a deep drawing manufacturing process. The projectile holding section 3 in this embodiment is however separately formed and welded to the conical portion 23 or major portion 25 of the tubular sleeve 16.

[0043] The projectile 6 extends from a pointed tip 18 to a trailing end 20. A centre section 22 of the projectile comprises a portion having a cylindrical shape that is coupled in a tight friction fit to a projectile holding section 3 of the casing.

[0044] The outer diameter of the trailing end is less than the diameter Dp of the centre section 22, as perse known, inter alia to facilitate insertion assembly of the projectile into the casing 4. In order to improve the aerodynamics of the projectile, the overall length Lp may be increased, or the curvature of the leading profile from the tip 18 to the waist in the center body section 22 may have an increased radius of curvature. This means that for a casing 4 of given dimensions, and an ammunition cartridge overall length L of given maximum dimensions, a longer projectile results in the trailing end 22 being inserted deeper within the cartridge casing, i.e. further away from the open end 33. A larger curvature of radius of the leading face of the projectile may have the effect that at the open end 33 of the casing 4, the casing does not grip on the projectile because it is curved in this region and not yet at its full outer cylindrical diameter Dp. In other words, with a larger radius of the leading profile of the projectile, the portion of the cylindrical center section 22 that is gripped by the projectile holding section 3 moves rearwardly and with a conventional cartridge would thus reduce the length of the casing part gripping the projectile. An improved aerodynamic profile of a projectile may lead to an increased radius of the leading profile, or a longer projectile, or both of the aforementioned features. An improvement in the aerodynamic properties of the projectile allows to increase the range and the flight accuracy of the projectile. It also reduces the kinetic energy loss of the projectile.

[0045] According to an aspect of the invention, in order to accommodate projectiles that have a greater length or a better aerodynamic profile as mentioned above, the projectile holding section has a tubular inner extension portion 5 that extends axially rearwardly into the tubular sleeve 16 thus increasing the section of the projectile holding section of the casing that grips onto the cylindrical center section 22 of the projectile.

[0046] In the embodiment of figures 1a to 1c, the projectile holding section 3 comprises a first holding part 3a that is formed by the tubular outer extension portion 24 of the tubular sleeve 16 and a separately formed second holding part 3b that is assembled within the casing and having a tubular inner extension portion 5 that extends rearwardly into the casing to increase the length of the holding part.

[0047] The separately formed second holding part 3b may comprise a fixing cone portion 7 and a substantially cylindrical tubular inner extension portion 5 extending therefrom, the fixing cone portion 7 being configured to be attached to an inner side of the conical transition portion 23 of the tubular sleeve 16 of the cartridge casing 4.

[0048] The second holding part 3b may in particular be attached by welding the fixing cone portion 7 to the conical transition portion 23 of the casing. The second holding part 3b may be assembled through the rear end 31 of the tubular sleeve 16 before the separately formed base 14 is then mounted over the rear end 31 and welded thereto.

[0049] The length Lginof the projectile second holding part 3b is preferably in a range of 0.2 to 0.5 of an overall length Lg of the projectile holding section 3 (0.2 <Lgjn / Lg < 0.5). This range allows adequate extension of the gripping section for extending the length of the projectile leading profile without adding unnecessary gripping friction. This ratio could larger than 0.5 if the projectile holding portion 24 is shortened, even completely cut away such that the casing shoulder 23 ends on the projectile 6, in which case the ratio Lgin / Lg may be 1 .

[0050] The tubular inner extension portion 5 may advantageously comprise venting holes 9 to limit the restriction on the evacuation of combustion gases, and possibly unburned propellant particles, out of the casing. These venting holes reduce also the pressure exercised by the combustion gases flow and eliminate possible deformations of the inner extension portion. The overall surface area of the venting holes will depend on the mechanical strength requirements of the tubular inner extension portion 5 for fixing stably the projectile, but may be reduced in size compared to the possible maximum size in order to limit the rate of combustion gas exiting the casing in situations where a restriction of the expansion rate is desired to control acceleration of the projectile. In other words, the size and arrangement of the venting holes 9 may be calibrated to control the gas expansion in the rifle barrel and thus the acceleration of the projectile.

[0051] In the embodiment of figures 2a and 2b, the projectile holding section 3 may comprise a separately formed part having both the first part 3a forming the tubular outer extension portion 24 and the second part 3b forming the tubular inner extension portion 5, the projectile holding section having a fixing cone portion 7 that is attached to the outer surface of the conical transition portion 23 of the tubular sleeve 16. In this case, the tubular sleeve 16 may be produced in a conventional manufacturing procedure except that the neck portion having the projectile gripping part as found in conventional casings is not provided and is replaced by the separately formed projectile holding section 3 that is then welded via its fixing cone portion 7 to the conical transition portion 23 of the casing tubular sleeve 16. List of referenced features

[0052] Ammunition cartridge 2

[0053] Casing 4

[0054] Base 14

[0055] Rim 27

[0056] Annular groove 29

[0057] Tubular sleeve 16 container portion 25 base end 31 conical transition portion 23 projectile holding portion 24 open end 33

[0058] Base to sleeve attachment (weld) 21

[0059] Projectile holding section 3

[0060] Fixing cone portion 7

[0061] Tubular inner extension portion 5 venting holes 9

[0062] Tubular outer extension portion (projectile holding portion) 24 open end 33

[0063] Projectile 6

[0064] Tip 18

[0065] Centre body portion 22

[0066] Trailing end 20

[0067] Ignition device 8

[0068] Propellant charge 10

[0069] A longitudinal centre axis of the projectile

[0070] L length of the cartridge

[0071] Lc length of the casing

[0072] Lp length of the projectile

[0073] Lg length of the projectile holding section

[0074] Lg,nlength of the tubular inner extension portion

Claims

Claims1. Ammunition cartridge comprising a casing (4), a propellant charge (10) contained inside the casing, an ignition device (8), and a projectile (6), the casing (4) including a base (14), a tubular sleeve (16) including a container portion (25) and a conical transition portion (23), and a projectile holding section (3), the base (14) closing a first end of the casing and the projectile holding section forming a second end of the casing, the conical transition portion interconnecting the projectile holding section to the tubular sleeve, the projectile holding section configured to hold the projectile (6) mounted at said second end of the casing, the projectile holding section comprising a first holding part (3a) comprising a tubular outer extension portion (24) extending axially forwardly from the conical transition portion (23) of the tubular sleeve (16) configured to grip a center body section (22) of the projectile (6), and a second holding part (3b) including a tubular inner extension portion (5) extending axially rearwardly and configured to grip the center body section (22) of the projectile, characterized in that the projectile holding section comprises a separately formed part fixed to the tubular sleeve of the casing by a weld connection, said separate part including at least said tubular inner extension portion (5).

2. The ammunition cartridge of the preceding claim, wherein the separately formed projectile holding section comprises a fixing cone portion (7) welded to the conical transition portion (23) of the tubular sleeve (16).

3. The ammunition cartridge of the preceding claim, wherein the separately formed holding part comprises said tubular inner extension portion (5) and the fixing cone portion (7) attached to an inner side of the conical transition portion (23) of the tubular sleeve (16), the first holding part (3a) being integrally formed with the tubular sleeve (16).

4. The ammunition cartridge according to claim 2, wherein the separately formed projectile holding section (3) comprises the tubular outer extension portion (24), the tubular inner extension portion (5) and the fixing cone portion (7).

5. The ammunition cartridge according to any preceding claim, wherein the base and tubular sleeve are made of stainless steel.

6. The ammunition cartridge according to any preceding claim, wherein the separately formed holding part is made of stainless steel.

7. The ammunition cartridge of any preceding claim, wherein the base (14) of the casing is separately formed from the tubular sleeve (16) and attached thereto by welding or crimping.

8. The ammunition cartridge according to any preceding claim 1-5, wherein the base (14) and tubular sleeve (16) of the casing are integrally formed as a single piece.

9. The ammunition cartridge according to any preceding claim, wherein a length Lginof the projectile second holding part (3b) is in a range of 0.2 to 0.5 of an overall length Lg of the projectile holding section (3).

10. The ammunition cartridge according to any preceding claim, wherein the tubular inner extension portion (5) of the projectile holding section (3) comprises venting holes configured to allow combustion gas and unburned propellant particles, to pass through the tubular inner extension portion (5).11 . Ammunition cartridge comprising a casing (4), a propellant charge (10) contained inside the casing, an ignition device (8), and a projectile (6), the casing (4) including a base (14), a tubular sleeve (16) including a container portion (25) and a conical transition portion (23), and a projectile holding section (3), the base (14) closing a first end of the casing and the projectile holding section forming a second end of the casing, the conical transition portion interconnecting the projectile holding section to the tubular sleeve, the projectile holding section configured to hold the projectile (6) mounted at said second end of the casing, the projectile holding section comprising a tubular inner extension portion (5) extending axially rearwardly from an end of the conical transition portion and configured to grip the center body section (22) of the projectile, characterized in that the projectile holding section comprises a separately formed part, said separate part including at least said tubular inner extension portion (5) and a fixing cone portion (7) welded to the conical transition portion (23) of the tubular sleeve (16).

12. The ammunition cartridge of the preceding claim, wherein the fixing cone portion is mounted against an inner side of the conical transition portion, the inner side facing an inside of the container portion.

13. The ammunition cartridge of the preceding claim 11 or 12, wherein the projectile holding section comprises a first holding part (3a) comprising a tubular outer extension portion (24) extending axially forwardly from the conical transition portion (23) of the tubular sleeve (16) configured to grip a center body section (22) of the projectile (6), and a second holding part (3b) comprising said tubular inner extension portion (5).

14. The ammunition cartridge of the preceding claim, wherein the first holding part (3a) is integrally formed with the tubular sleeve (16).

15. The ammunition cartridge according to any preceding claim 11-14, wherein the base and tubular sleeve are made of stainless steel.

16. The ammunition cartridge according to any preceding claim 11-15, wherein the separately formed holding part is made of stainless steel.

17. The ammunition cartridge of any preceding claim 11-16, wherein the base (14) of the casing is separately formed from the tubular sleeve (16) and attached thereto by welding or crimping.

18. The ammunition cartridge according to any preceding claim 11-17, wherein a length Lginof the projectile second holding part (3b) is in a range of 0.2 to 0.5 of an overall length Lg of the projectile holding section (3).

19. The ammunition cartridge according to any preceding claim 11-18, wherein the tubular inner extension portion (5) of the projectile holding section (3) comprises venting holes configured to allow combustion gas and unburned propellant particles, to pass through the tubular inner extension portion (5).

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