A self-centering anti-dry fire device for a crossbow n improved crossbow lock mechanism assembly includes a trigger housing, a string latch, a seer lever, a combination arrow self-centering anti-dry fire and seer lock lever, a trigger and a safety slide bar. An arrow cavity is formed in a top of the combination arrow self-centering anti-dry fire and seer lock lever. A cross section of the arrow cavity may have a “V” shape, a curved shape, a notch shape or any other suitable shape. The arrow cavity ensures that the arrow shaft is centered relative to a centerline of a barrel of the crossbow.