Checking AR-15 Firing Pin Protrusion
This guide details four methods for measuring firing pin protrusion on AR-15, M16, and M4 platforms, presented by School of the American Rifle. Proper protrusion is crucial for reliable primer ignition and preventing primer piercing. The methods include using a depth/anvil gauge, a caliper, a specialized firing pin protrusion gauge, and a government-issue style gauge. The recommended range for firing pin protrusion is typically between 0.028" and 0.036".













