Brownells AR-15/M16 Firing Pin Protrusion Gauge Features The Brownells AR-15/M16 Firing Pin Gauge gives gunsmiths and armorers a fast reliable way to measure exactly how far the firing pin protrudes through the bolt face. This measurement is critical to safe and reliable function since insufficient protrusion can lead to light strikes and misfires while excessive protrusion can pierce primers and cause dangerous overpressure events. Constructed from steel the gauge is built to hold its precise dimensions through repeated use in a shop or armory setting. Its compact 2 inch length and 1/4 inch width make it easy to use directly against the bolt face without needing additional tools or fixtures. Regular use of this gauge as part of routine maintenance helps catch worn or out-of-spec firing pins before they cause a failure in the field. It is a valuable tool for anyone building inspecting or troubleshooting AR-15 and M16 pattern rifles whether professionally or as a serious home gunsmith. Because it is purpose-built for this single measurement the gauge delivers consistent repeatable readings that a caliper or improvised method cannot easily match. Adding this gauge to a maintenance kit is a simple way to keep an AR-15 platform running safely and reliably over the long term. Brownells AR-15/M16 Firing Pin Protrusion Gauge Specifications Manufacturer: Brownells Model: AR-15/M16 Firing Pin Protrusion Gauge Material: Steel Length: 2 Width: 1/4 Available At: GrabAGun