A weaponized UUV has a sliding barrel and accessible breech. The barrel slides in response to the firing of a projectile, and moves a first distance un-arrested, providing time for the projectile to clear the barrel. After the projectile clears the barrel, a recoil mechanism engages the barrel, transferring the recoil load to the hull of the UUV.

A weaponized UUV has a sliding barrel and accessible breech. The barrel slides in response to the firing of a projectile, and moves a first distance un-arrested, providing time for the projectile to clear the barrel. After the projectile clears the barrel, a recoil mechanism engages the barrel, transferring the recoil load to the hull of the UUV.

A barreled firearm having a mass-locked breechblock and a recoil-damping element which is connected on one side to a frame assembly and on another side to a barrel assembly including a barrel. A housing part of the barrel assembly is mounted in the frame assembly in an axially slidable manner. A support element stationary relative to the barrel is mounted in a breechblock housing or in the frame assembly in an axially slidable manner. Alternatively, a support element stationary relative to the frame assembly is mounted in a breechblock housing in an axially slidable manner. The breechblock housing is guided by the frame assembly in an axially slidable manner and the breechblock housing is supported by the support element by means of a spring element. This design absorbs or reduces recoil when a shot is fired from the barreled firearm.