| 摘要 |
A firearm comprises a barrel having a bore and a receiver forming an ignition chamber. A bolt is slidable in the ignition chamber and includes a striker projection for igniting a primer of the projectile. A bolt advancing mechanism comprises an arm having a first end mounted on the bolt such that a second end of the arm is movable laterally relative to the fore-aft axis. A boss is carried at the second end of the arm. An actuator member is movable in the fore-aft direction relative to the bolt and boss, and includes a first cam surface inclined relative to the fore-aft axis for urging the boss forwardly and laterally. The boss is movable laterally along the first cam surface in response to the boss becoming aligned with a lateral groove in the receiver. Such lateral movement of the boss is in a direction tending to displace the bolt forwardly. The actuator member (i) pushes the boss and bolt forwardly to shift the projectile to a firing position, (ii) cams the boss into the groove to further displace the bolt forwardly and ignite the primer, and (iii) blocks movement of the boss from the groove until ignition occurs, whereupon a second cam surface displaces the boss outwardly. |
