AR-15 Bolt Carrier Group Completion Kit - 5.56/.300

AR-15 Bolt Assembly 9310 Steel Nitride MPI - .223 / 5.56 / .300 AAC

Ensure peak cycling performance and structural reliability in your rifle with the AR-15 Bolt Assembly 9310 Steel Nitride MPI. Precision-engineered and 100% manufactured in the USA, this completely assembled replacement bolt group is built to handle high-volume firing schedules across .223 Remington, 5.56x45mm NATO, and .300 AAC Blackout platforms.

Machined from premium 9310 alloy steel, the bolt body undergoes Magnetic Particle Inspection (MPI) to detect microscopic surface defects and ensure long-term structural integrity. Finished in a slick, slick-cleaning black nitride coating, it includes a durable black oxide extractor equipped for positive extraction under heavy action. Arriving fully assembled with gas rings, extractor assembly, and ejector pre-installed, this unit is a true drop-in upgrade or essential component for any custom BCG build.

Key Features

• Made in the USA: Manufactured to precise mil-spec tolerances for dependable performance and perfect fitment.
• 9310 Alloy Steel Construction: Premium alloy steel construction delivers superior tensile strength and fatigue resistance compared to standard carbon steels.
• MPI Tested (Magnetic Particle Inspected): Individually inspected to ensure freedom from micro-fractures, voids, or material flaws.
• Corrosion-Resistant Black Nitride Finish: Hardened surface treatment provides high lubricity, wear resistance, and easy carbon cleanup.
• Heavy-Duty Black Oxide Extractor: Built for smooth, reliable shell extraction under rapid fire and adverse field conditions.
• Multi-Caliber Versatility: Fully compatible with .223 Remington, 5.56 NATO, and .300 AAC Blackout caliber setups.
• Completely Assembled Drop-In Part: Pre-assembled with extractor, ejector, and gas rings for effortless installation into any standard AR-15 bolt carrier.