Firearms

In a firearm including housing means having a charge-detonating chamber for receiving a compressably ignitable charge, projectile discharge means communicating with said chamber and being arranged to receive a projectile which is independent of said charge;

• bolt means displaceably mounted in said chamber for movement between a cocked position and a charge-detonation position;
• force-storing means arranged to urge said bolt means toward said detonation position during a detonation stroke;
• locking means disposed between said force storing means and said bolt means to prevent return of said bolt means to said cocked position while permitting continued movement of said bolt means to complete said detonation stroke;
• means for shifting said locking means to an unlocking position subsequent to discharge of said projectile to permit return of said bolt means to said cocked position;
• displaceable means mounted adjacent the discharge end of the said discharge means for forward displacement relative thereto;
• said displaceable means having reaction surface means positioned to be contacted and driven forwardly by combustion gases from said discharge means;
• and means for transmitting energy from said displaceable means in a manner tending to resist recoil forces;
• said shifting means being connected to said displaceable means for automatically shifting said locking means to its unlocking position in response to forward movement of said displaceable means.

In a firearm comprising barrel means, a charge detonation chamber, bolt means shiftable relative to said chamber, movable locking means including a stop for locking said bolt means against movement away from a charge disposed in said chamber during firing of a projectile, and means for automatically unlocking said bolt subsequent to firing, said unlocking means comprising:

• displaceable means mounted adjacent a discharge end of said barrel means for displacement relative thereto, said displaceable means including:
• reaction surface means positioned to be acted upon, and displaced, by combustion gases from said barrel means;
• and
• a piston slidably mounted in a muzzle end of said barrel means, said piston having a central aperture for discharging a projectile;
• and
• means connecting said displaceable means with said locking means to shift said locking means to a position unlocking said bolt means in response to firing said firearm;
• said connecting means comprising a rod connected to said displaceable means and to said locking means.