The Rock River Arms 5.56×45 Bolt Carrier Group (brand part no. AR0032BGRP) is a full-auto profile carrier finished in durable phosphate for AR-15 and M16-pattern uppers. The heavier full-auto carrier geometry runs reliably in both semi-automatic and full-auto lower receivers, making it a versatile upgrade or replacement for a duty or range rifle. The phosphate finish resists corrosion and holds lubricant well, which keeps the action running cleaner between cleanings. It’s a straightforward, mil-spec-dimensioned swap for anyone building or refreshing a 5.56 AR-15 upper.

Key Specifications

• Chambered for 5.56×45 NATO, the standard AR-15/M16 platform caliber.
• Machined with a full-auto carrier profile, compatible with both semi-automatic and full-auto lower receivers.
• Finished in phosphate for corrosion resistance and reliable lubricant retention.
• Built as a direct-fit AR-15 accessory for standard mil-spec upper receivers.
• Measures approximately 9.25 inches overall.

Frequently Asked Questions

Will this run in a semi-automatic-only lower? Yes, a full-auto profile carrier functions in both semi-automatic and full-auto lower receivers.

What finish does it use? A phosphate finish, chosen for its corrosion resistance and ability to hold lubricant during hard use.

Is it chambered for .223 Remington too? Yes, 5.56×45 NATO chambers safely fire .223 Remington ammunition.

Buy the Rock River Arms 5.56 Bolt Carrier Group

A mil-spec-dimensioned, full-auto profile carrier is a dependable way to refresh a worn upper or finish a new build. Order it from Rock River Arms through our Lubbock, Texas gun shop for fast, direct shipping, and browse more AR bolt carrier groups to complete your upper.