The Colt M4 Spirol Pin is a factory-original receiver component engineered specifically for Colt AR-15 and M4 platforms, including compatible M16 configurations. Designed to maintain alignment and structural integrity within the upper and lower receiver assemblies, this small but critical pin supports smooth cycling and consistent lockup during regular use and detailed maintenance.

This Spirol pin is ideal for owners who want to keep their rifle running with authentic Colt parts, whether they are refreshing a well-used service rifle or completing a careful rebuild. Its precise fit helps prevent unwanted play in the receiver system, contributing to predictable trigger feel and reliable feeding and extraction at the range or in training. Backed by Colt’s long-standing reputation for dependable firearms, the M4 Spirol Pin offers a straightforward way to preserve the performance and longevity of your AR-15/M4.

• Manufacturer: Colt
• Model: M4 Spirol Pin
• Platform: AR-15/M4, M16
• Component Type: Receiver pin
• Intended Use: Maintenance, repairs, and rebuilds