Safety mechanism for blowback firearm

A breechblock assembly for a firearm, comprising:

• a breechblock extending along a central axis and configured to reciprocate along a receiver of the firearm between a recoil position and a battery position;
• a hammer or striker coupled to the receiver and movable between a cocked position and a fire position;
• a lever on the breechblock, the lever movable between a blocking position and a non-blocking position in response to the breechblock moving between the recoil position and the battery position, respectively;
• and
• a spring configured and arranged to bias the lever to the blocking position;
• wherein when the lever is in the blocking position, the lever blocks the hammer or striker from moving to the fire position, thereby preventing the firearm from firing.

An auto-loading firearm comprising:

• a receiver including a cam surface;
• a hammer or striker coupled to the receiver and movable between a cocked position and a fire position;
• a breechblock configured to reciprocate along the receiver between a recoil position and a battery position;
• an actuator on the breechblock, the actuator positioned to engage the cam surface on the receiver when the breechblock is within a predefined distance from the battery position;
• a lever configured to be actuated by the actuator to move from a blocking position to a non-blocking position when the actuator engages the cam surface;
• and
• a spring arranged to bias the lever to the blocking position;
• wherein when the breechblock is out of the battery position by more than the predetermined distance, the actuator is in a first position and the lever is in the blocking position, and when the breechblock is within the predefined distance of the battery position the actuator is in a second position and the lever is in the non-blocking position.