Colt M16/M4/AR15 Bolt Carrier Key

Colt M16 / M4 / AR-15 Bolt Carrier Key SP61547 – 5.56mm Gas Key

Factory Colt SP61547 Bolt Carrier Key (commonly called the Gas Key) for M16, M4, and AR-15 5.56mm bolt carrier assemblies.

This key is a critical part of the Colt AR-15 gas system. It mounts to the top of the bolt carrier and channels gas from the gas tube into the carrier to cycle the action. Precision-machined for proper fit and reliable function on mil-spec and Colt-pattern carriers. Ideal as a replacement or spare for builds, repairs, and maintenance.