Anti-Walk Trigger Pins

Anti-walk trigger pins solve a persistent problem with AR-15 lower receivers: trigger and hammer pin migration under recoil. Standard pins can gradually "walk" out of spec holes over time, particularly with drop-in trigger cassettes that don't interact with the receiver walls the same way as traditional triggers. This migration can cause trigger malfunctions, inconsistent pull characteristics, and in extreme cases, complete failure to fire.

These specialized pins feature a threaded design that locks them in place using set screws, typically accessed with Allen keys. The threaded section prevents any lateral movement while the set screws provide positive retention even under sustained recoil. Most anti-walk pins maintain the standard .154" diameter for compatibility with small pin AR-15 lowers, though .172" versions exist for large pin Colt receivers produced between 1991 and 2009.

Anti-walk pins are essential for many drop-in trigger systems, particularly cassette-style triggers from manufacturers like CMC, Elftmann, and Timney. While some traditional triggers don't require them, installing anti-walk pins is good preventive maintenance that eliminates a potential failure point. The installation is straightforward, and the improved reliability is well worth the minimal investment, especially on rifles seeing heavy use or equipped with premium triggers.