A method for inserting a safety block into a rifle comprising upper and lower receivers, the lower receiver comprising a trigger assembly positioned within a cavity. The method includes separating the upper receiver and the lower receiver to expose the lower receiver and inserting the safety block into the cavity. The safety block comprises a hammer cavity that surrounds the trigger assembly such that the safety block surrounds at least a hammer of the trigger assembly. A hammer stop of the safety block rests against the hammer. The upper receiver is then closed against the lower receiver. Closing the upper receiver brings the upper receiver into contact with the safety block and rotationally pushes the hammer stop of the safety block forward and against the hammer. Rotating the safety block against the hammer rotates the hammer to free the hammer from a restraining portion of the trigger assembly.

A method for inserting a safety block into a rifle comprising upper and lower receivers, the lower receiver comprising a trigger assembly positioned within a cavity. The method includes separating the upper receiver and the lower receiver to expose the lower receiver and inserting the safety block into the cavity. The safety block comprises a hammer cavity that surrounds the trigger assembly such that the safety block surrounds at least a hammer of the trigger assembly. A hammer stop of the safety block rests against the hammer. The upper receiver is then closed against the lower receiver. Closing the upper receiver brings the upper receiver into contact with the safety block and rotationally pushes the hammer stop of the safety block forward and against the hammer. Rotating the safety block against the hammer rotates the hammer to free the hammer from a restraining portion of the trigger assembly.

A firearm lock mechanism includes a trigger, a hammer, a stirrup connected to the hammer at a stirrup connection point, and a spring operably connected to the stirrup at a spring connection point. Progressive pivoting of the trigger drives corresponding progressive pivoting of the hammer. The stirrup connection point is disposed forward of the hammer pivot point. One of the spring connection point, hammer pivot point, and stirrup connection point is offset relative to and laterally spaced between the others of the points to be a vertex of an intermediate angle cooperatively defined by the points. The angle increases in magnitude as the trigger drives pivoting of the hammer. A toggle line is defined between the trigger pivot point and the hammer pivot point. The trigger contacts the hammer at a contact point that shifts across the toggle line as the trigger drives pivoting of the hammer.

A firearm lock mechanism includes a trigger, a hammer, a stirrup connected to the hammer at a stirrup connection point, and a spring operably connected to the stirrup at a spring connection point. Progressive pivoting of the trigger drives corresponding progressive pivoting of the hammer. The stirrup connection point is disposed forward of the hammer pivot point. One of the spring connection point, hammer pivot point, and stirrup connection point is offset relative to and laterally spaced between the others of the points to be a vertex of an intermediate angle cooperatively defined by the points. The angle increases in magnitude as the trigger drives pivoting of the hammer. A toggle line is defined between the trigger pivot point and the hammer pivot point. The trigger contacts the hammer at a contact point that shifts across the toggle line as the trigger drives pivoting of the hammer.

A firearm lock mechanism includes a trigger, a hammer, a stirrup connected to the hammer at a stirrup connection point, and a spring operably connected to the stirrup at a spring connection point. Progressive pivoting of the trigger drives corresponding progressive pivoting of the hammer. The stirrup connection point is disposed forward of the hammer pivot point. One of the spring connection point, hammer pivot point, and stirrup connection point is offset relative to and laterally spaced between the others of the points to be a vertex of an intermediate angle cooperatively defined by the points. The angle increases in magnitude as the trigger drives pivoting of the hammer. A toggle line is defined between the trigger pivot point and the hammer pivot point. The trigger contacts the hammer at a contact point that shifts across the toggle line as the trigger drives pivoting of the hammer.

A firearm lock mechanism includes a trigger, a hammer, a stirrup connected to the hammer at a stirrup connection point, and a spring operably connected to the stirrup at a spring connection point. Progressive pivoting of the trigger drives corresponding progressive pivoting of the hammer. The stirrup connection point is disposed forward of the hammer pivot point. One of the spring connection point, hammer pivot point, and stirrup connection point is offset relative to and laterally spaced between the others of the points to be a vertex of an intermediate angle cooperatively defined by the points. The angle increases in magnitude as the trigger drives pivoting of the hammer. A toggle line is defined between the trigger pivot point and the hammer pivot point. The trigger contacts the hammer at a contact point that shifts across the toggle line as the trigger drives pivoting of the hammer.