Ammunition.

FIELD OF INVENTION This invention relates to a round of ammunition.

BACKGROUND

It is known to form a round of ammunition having two chambers, one containing a charge and the other providing a space which facilitates a generally even distribution of the pressure acting on a projectile. The present invention provides a novel and inventive adaptation of that type of ammunition.

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 projectile engaged with the case, a chamber between the case and the projectile, and a resilient ring providing a tight sealed fit between the case and the projectile, the round formed such that when it is fired combustion gases are formed in the case and travel into the chamber to cause the sealed fit to break and the projectile to propel from the case.

Preferably the resilient ring is located within a groove in the periphery of the projectile.

Preferably the resilient ring comprises an O-ring.

Preferably the case comprises an insert which contains the charge.

Preferably the insert is replaceable such that the case, less the insert, is reusable.

Preferably the chamber is an effective low pressure chamber relative to the case.

Preferably there is a leaf between the case and the chamber and, when the round is fired, gas in the case is able to blow through the leaf and enter the chamber when such gas reaches a predetermined pressure.

Preferably the leaf is metallic.

Preferably the projectile is substantially formed from a suitable polymer.

Preferably the resilient ring is formed from a suitable synthetic polymer.

DESCRIPTION OF THE DRAWINGS / 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 side cross section exploded view of a round of ammunition,

Figure 2 is a side cross section view showing the round when assembled, and

Figure 3 is an isometric view of the round when assembled.

DETAILED DESCRIPTION

As shown in the drawings the round of ammunition comprises a metallic case 1 and a projectile 2. Preferably the round of ammunition is a 40 mm round. The case 1 incorporates an insert 3 containing explosive material 4 sufficient to enable the round to be fired from a rifle or some other suitable firearm. The insert 3 is replaceable after the round has been fired so that the case 1 (less its original insert) may be re-used.

The projectile 2 engages the case 1 in a tight sealed fit by way of a resilient CD- ring 5. The O-ring 5 thus provides sufficient friction to hold the case 1 and projectile 2 together, ready for firing, as a low pressure low velocity round of ammunition. It is thus not necessary for the case 1 and the sabot 2 to be crimped, screw fitted or glued to one another. As shown in figure 2, when the round is assembled the O-ring 5 is seated within a groove 6 in the periphery of the projectile 2. Preferably the O-ring 5 is formed from a suitable synthetic polymer. As shown in figure 2, when the projectile 2 is within the case 1 there is a space 7 between the two. The space 7 serves as a low pressure chamber.

When the round is fired from a suitable firearm the explosive material in the insert 3 explodes such that the insert becomes a high pressure chamber. When gas pressure within the insert 3 reaches a certain level the gases blow through a metallic leaf 3a or the like, as is known in the art, and enter the space or low pressure chamber 7. The use of the low pressure chamber 7 between the case 1 and the projectile 2 reduces stress on the round as it is fired. When gas pressure within the low pressure chamber 7 reaches a certain level the O-ring seal between the case 1 and the projectile 2 breaks and the projectile launches from the case towards its target. Preferably the O-ring 5 gives the round sufficient effective backpressure to enable it to be used for targets up to 400 metres away.

Preferably the projectile 2 is formed from a suitable synthetic polymer so that the round can be used in a training context rather than as actual combat ammunition. Preferred forms of the round enable cost savings as the case 1 can be re-used, for example by fitting it with a new insert 3 and projectile 2 after it has been fired. The use of an O-ring 5 means that a new projectile can be fitted without the need for heavy duty machinery.

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.