Geissele Automatics Trigger Fitting Pin 02-313 AR-15/AR-10

The Geissele Automatics Trigger Fitting Pin (MPN 02-313) is a purpose-built gunsmith's tool designed to assist with AR-15 and AR-10 trigger and hammer installations. The fitting pin is cut to the exact size of the platform's trigger and hammer pins, letting it stand in for an actual trigger or hammer pin while you align and seat the roll pin that retains the fire-control group inside the lower receiver. Made from steel with a black handle, it is a controlled, repeatable alternative to nudging a real trigger or hammer pin with a punch and hammer.

The pin's 0.154" O.D. is correctly sized for both trigger and hammer pin holes in small-pin AR-15 / LR-308 lowers, so a single tool covers full disassembly and reassembly of the lower's fire-control group. It also accommodates the 0.078" diameter roll pin that retains the trigger and hammer assembly, keeping your rifle in pristine condition while you swap triggers. Compact, simple, and made by Geissele Automatics, the Trigger Fitting Pin earns a permanent spot on any armorer's bench or home-builder's build mat.