Patient status

GB 1917405.1 & PCT/GB2019/000163, GB 1917306.1 & PCT/GB2019/000162, GB 1917235.2 & PCT/GB2019/000161.

Commercial rights

Sole Rights / Non-exclusive







Available to license


Project number


A new design for captive piston ammunition that makes it viable for a range of firearms.

Captive piston projectile ammunition has the benefit of eliminating flash and reducing the noise when a round is discharged. However, previous designs have suffered from a number of limitations resulting in them being adopted by specialist users only. This new design makes captive piston ammunition a viable alternative to conventional munitions.

Dstl’s new design resolves issues with previous designs by housing the piston mechanism within the projectile (as opposed to in a cartridge or specialist barrel). It carries the potentially dangerous pressurised gas (sealed within the projectile) away from the user and removes undesirable heat signature from the weapon.


  • Reduced Signature — No flash, significant noise suppression, and the elimination of any heat signatures left by spent ammunition / empty cases reduces the user’s signature.
  • Compatible with Conventional Weapons — the design can be fired from conventional firearms and adapted for a range of calibres.
  • Maximises Payload — the novel launch mechanism design maximises the space available to store the payload.
  • Safer — due to the hot / high-pressure gases being taken away from the user.
  • Alternative Fuse System — the captive gas can be used to trigger additional ammunition functionality (e.g. igniting fuzes for grenade effects).
  • Consistent Performance — compared with flash suppressors / specialist powders (e.g. smokeless, faster-burning propellants).

Test Rig

A ballistic test rig has also been developed specifically to test the new design. Unlike conventional ballistic characteristic measurement methods which use either extrapolation or inference from external measurements, this test rig directly measures speed and pressure over time. The test rig is highly configurable. The geometry inside the test area can be varied to simulate different gun barrel chambers or cartridge designs.

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