Patent attributes
A semiautomatic firearm with a reciprocating bolt assembly has delayed blowback and a firing pin block. The firearm is particularly suitable for firing necked rimfire cartridges with a high level of reliability. Features prevent out-of-battery firing, when the bolt assembly is not fully engaged to the firing chamber or barrel face, a movable member within a bolt body functions as a blocking member that blocks the firing pin and prevents the firing pin from striking a cartridge. In embodiments, the firing pin has two stop portions that the movable member can engage depending on the cycle status of the firearm. A reverse cam mechanism associated with the firing pin blocking provides a resistance to and delays blowback. The bolt may interface with the necked rimfire cartridge using a undercut engagement on the forward end of the bolt. The semiautomatic firearm also may incorporate one or both of a dual trigger arrangement as part of a trigger and firing mechanism.
