A contained Davis gun system enables misfire and hang-fire handling for fire out of battery (also known as soft recoil). The gun system decreases structural dynamic activity of the gun barrel during launch with resulting increases in system accuracy. The gun system further presents synergistic advantages when combined with a conventional recoil system in a double recoil design. The gun system includes a non-recoiling barrel and a recoil system engineered to contain a recoiling inertial breechblock capable of translating within the gun barrel. The recoil system includes a brake and a spring secured to a mount fixture. The breechblock enables the loading of the propellant and the projectile within the barrel, and further enables pressure to be contained within the barrel during firing. The recoil system applies a load to the breechblock, which is a function of the breechblock position and its velocity within the barrel. A part of the kinetic energy imparted to the breechblock is stored as potential energy within the spring, and the remaining kinetic energy is dissipated by the brake as heat. Prior to firing, the barrel and the recoil system are coupled to the firing platform. When the propellant is ignited, propellant gases generated by the propellant propel the projectile forward along the gun barrel while propelling the inertial breechblock rearward within the gun barrel.

A bolt carrier assembly has a housing (300) for supporting a bolt (317) and a P cross-sectionally shaped member (301) having the longer side of the P-shape secured to the housing, the P-shaped member being forwardly extended with respect to the bolt. The main drive spring (307) is located alongside the wrapped-over portion of the P-shaped member which main drive spring is arranged to provide motion to the housing and P-shaped member. An anti-bounce weight (354) is mounted inside the wrapped-over part of the P-shaped member and has a spring at one end which is compresed by the anti-bounce weight when the P-shaped member is suddenly retarded by the housing to which it is attached striking the barrel assembly. A latch (326-329) is spring biassed and shaped and dimensioned to interleave locking lugs (322) on the bolt (317), the latch being longitudinally retractable with respect to the housing.

A self-contained blowback-type firing unit insertable in a gun body as a discrete subassembly and including a barrel and bolt with a compression spring acting between them, characterized in that the barrel and bolt slide together on matching longitudinal track surfaces which are other than cylindrical and circumferentially complete, the bolt being slideable on no surfaces other than the barrel track surfaces.

A device that is capable of adjusting the volume available to combustion gases following their expansion in a firearm includes (i) an expansion chamber connected to the barrel of the firearm through (ii) at least one connection hole disposed near the beginning of the rifling; (iii) a front calibration screw capable of being rotated into or out of the expansion chamber so as to calibrate the firearm for a particular ammunition; and (iv) a back calibration screw capable of being rotated into or out of the expansion chamber so as to calibrate the firearm for a particular ammunition. Adjustment of the positions of the front calibration screw and the back calibration screw facilitates the adjustment in the volume of the expansion chamber. By virtue of the adjustable volume expansion chamber, it is possible to adapt the physical features of the firearm to the specific type of ammunition that is to be employed, such as, for example, a high charge load cartridge.

A recoil control mechanism for a weapon which fires a projectile which is characterized by the generation of a forward counterforce to the rearward recoil simultaneously with absorption of rearward recoil force upon initiation of propoulsion of the projectile. The forward counterforce is generated by propelling a first mass forwardly upon firing the projectile and substantially simultaneously propelling a second mass rewardly for absorbing some of the recoil force. In one mechanism (10), the first mass may be the weapon's barrel (12) and the second mass its breach block (14). Expaning gases (36) from detonation of propellant in cartridge (24) enter a reaction volume (28) between the barrel (12) and breech block (14). These gases drive barrel (12) forwardly against force transmission spring (16) to impose a forward counterforce on the weapon's frame (18). Substantially simultaneously recoil from detonation of cartridge (22) together with the gasses (36) in reaction volume (28) drive breech block (14) rearwardly against force absorbing spring (20).