AU2006202030A1 - Ammunition - Google Patents

Description

(TITLE

.Ammunition.

00 FIELD OF INVENTION This invention relates to a round of ammunition which can be fired from a weapon.

O

BACKGROUND

It is known to form a round of ammunition having two chambers, one containing a 1 0 charge and the other providing a space which facilitates more even distribution of Sthe pressure acting on a projectile. A problem with some known two-chamber rounds is that they can be prone to jamming in a firearm. It is accordingly an object of a preferred form of the invention to go at least some way towards addressing this problem, or to provide the public with a useful choice.

The term "comprising" or derivatives thereof, if and when used in this document should be interpreted non-exclusively, eg to mean "consisting of or including".

SUMMARY OF THE INVENTION According to one aspect of the invention there is provided a round of ammunition having a case loaded with a charge, a sabot engaged with the case such that a first part of the sabot is adjacent the charge, the sabot having a channel proceeding from adjacent the charge to a groove in the sabot, sealing means within the groove to substantially seal the sabot with respect to the case, and a second part of the sabot adjacent the groove and having a substantially wider cross sectional area than the first part of the sabot; the round being formed such that when it is fired from a weapon gases from the charge can proceed along the channel to the groove to break the seal provided by the sealing means and then proceed from the groove to exert pressure against the wider second part of the sabot to cause the sabot to propel from the case and the weapon.

Preferably the second part of the sabot is a peripheral portion of the sabot immediately adjacent the case.

D 2 Preferably the groove extends around the sabot between the first and second parts of the sabot.

00 Preferably the sealing means comprises a substantially resilient o-ring. In some embodiments of the invention it may involve a settable sealant.

SPreferably the sabot has a cavity and a separate nose cone which is applied to Sclose off the cavity. The cavity may contain a marker substance ie the round may not be live.

CPreferably the round has only one gas pressure chamber.

DESCRIPTION OF THE DRAWINGS I IMAGES Some preferred forms of the invention will now be described by way of example and with reference to the accompanying drawings, of which Figure 1 is a cross sectional perspective view through a round of ammunition for a firearm, Figure 2 is an exterior perspective view of the round, and Figure 3 is a cross sectional view of a portion of a sabot forming part of the round.

DETAILED DESCRIPTION Referring to figure 1 the firearm comprises a sabot 1 incorporating a nose cone 2, and a case 3 having a primer pocket 4. The primer pocket 4 is loaded with a suitable charge (not shown). As shown, the lower end of the sabot defines a boundary of the primer pocket 4.

Referring to figures 1 and 3, a channel 6 within the sabot extends upwards from immediately adjacent the primer pocket and then radially outwards to a groove 7 around a peripheral lower first part of the sabot. The groove houses an o-ring 8 O 3 S(shown in figure 1 only) which provides a seal between the sabot 1 and the case 3.

00 As indicated in figure 1, the primer pocket 4 is created by a way of a primer pocket insert 9 fitted to the rest of the case by way of a screw thread 10. The nose cone 2 is screw or snap fitted to the rest of the sabot to close off a cavity 11 Shousing a payload (not shown). The payload may include a marker material, for Sexample a suitable dye or debris such as talc or polystyrene beads, etc.

D 10 When in use the round is loaded into a weapon automatically or manually, and Sfired. As the round is fired the charge explodes within the primer pocket creating Cgases at extremely high pressure. These gases proceed up into the sabot 1 and outwards to the groove 7, all by way of the channel 6. When the gases arrive at the groove 7 they break the seal provided by the o-ring 8, preferably shearing the o-ring, and then proceed around the periphery of the sabot between the case and the sabot to contact a circular ledge or circular wider part 12 of the sabot. As the gases are now in forceful contact with a wider cross section of the sabot they propel the sabot from the case. In a sense the gases may be considered to move the sabot to create a secondary pressure chamber between the case 3 and the sabot. The sabot travels as a projectile to the desired target, and on contact therewith the nose cone breaks to release the marker material.

As shown in figures 1 and 3, the ledge or wider part 12 of the sabot angles outwards and upwards when the round is in a "case down nose cone up orientation. The degree of angle of the wider part 12 can be formed according to the overall dimensions and requirements for the round.

In some embodiments of the invention the round may have a second o-ring 13 located in a groove at the periphery of the sabot slightly above the ledge or wider part 12 mentioned above. The second o-ring provides a further but less substantial seal between the case and the sabot.

Referring to figure 1, the lower end 14 of the sabot is generally concave and has outer edges 15 which proceed slightly into, and are in tight fitting relationship 4 l with, the sides of the primer pocket. The primer pocket may incorporate a thin 1 copper lining adjacent the lower end 14 of the sabot. The lining is blown through as gases move from the primer pocket (ie the high pressure chamber) into the 00 channel 6. However in particularly preferred embodiments of the invention the lining is absent.

Those skilled in the art will appreciate that an advantage of the present invention Srelates to its use of only one pre-formed pressure chamber (ie the primer pocket).

OThe overall design obviates the need for a traditional secondary pressure chamber which assists in reducing the likelihood of a round jamming in the weapon used to fire the round. The weapon may be a GMG machine gun, a rifle, C or any other suitable firearm, etc. Preferably the round of figures 1-3 is a high velocity round suitable for use in 40 mm firearms.

In some embodiments of the invention the sabot may be formed from a zinc material, the primer pocket insert from steel, the rest of the case from an extruded aluminium material, the nose cone from plastic, and the o-ring from a suitable neoprene material. In some embodiments of the invention the round may be live, ie an item of ammunition for military combat rather than for training purposes.

While some preferred forms of the invention have been described by way of example it should be appreciated that modifications and improvements can occur without departing from the scope of the following claims.

Claims (9)

1. A round of ammunition having a case loaded with a charge, a sabot 00 engaged with the case such that a first part of the sabot is adjacent the charge, the sabot having a channel proceeding from adjacent the charge to a groove in the sabot, sealing means within the groove to substantially seal the sabot with Srespect to the case, and a second part of the sabot adjacent the groove and Shaving a substantially wider cross sectional area than the first part of the sabot; the round being formed such that when it is fired from a weapon gases from the charge can proceed along the channel to the groove to break the seal Sprovided by the sealing means and then proceed from the groove to exert Cpressure against the wider second part of the sabot to cause the sabot to propel from the case and the weapon.

2. A round according to claim 1, wherein the second part of the sabot is a peripheral portion of the sabot immediately adjacent the case.

3. A round according to claim 1 or 2, wherein the groove extends around the sabot between the first and second parts of the sabot.

4. A round according to claim 1, 2 or 3, wherein the sealing means comprises a substantially resilient o-ring.

A round according to any one of the preceding claims, wherein the sabot has a cavity and a separate nose cone which is applied to close off the cavity.

6. A round according to claim 5, wherein the cavity contains a marker substance.

7. A round according to any one of the preceding claims, wherein the round has only one gas pressure chamber. IC 6

8. A round according to any one of the preceding claims substantially as >herein described. 0

9. A round according to any one of the preceding claims, formed and arranged such that an effective secondary pressure chamber is only created on movement of the sabot caused by gases from the charge. A round substantially as herein described with reference to the Saccompanying drawings. c-I 2O