Brownells Ar-308/M16 7.62X39mm Bolt Carrier Group, Mpi, Nitride

Building an AR platform rifle in 7.62x39 requires a bolt carrier group engineered specifically for the cartridge, and the Brownells AR-308/M16 7.62x39mm Bolt Carrier Group delivers the precision component you need to complete a reliable, hard-use rifle. Whether you're assembling a 7.62x39 AR from a stripped lower or replacing a worn carrier, this MPI-inspected, nitride-finished BCG is built to the exacting standards serious builders and shooters demand.

The bolt itself is fully machined from 9310 steel—a premium alloy chosen for its toughness and consistency—then heat-treated and shot-peened to handle the pressures of centerfire rifle fire. The carrier comes from 8620 hardened steel, offering the durability needed for thousands of rounds downrange. The gas key is torqued and staked per military spec, and the extractor is assembled with a rubber insert and spring to ensure positive case extraction cycle after cycle. Every completed assembly undergoes magnetic-particle inspection—a professional-grade quality check that catches surface and near-surface defects invisible to the eye.

Finish matters when you're running a gun hard. The black-nitride coating provides genuine corrosion resistance without the brittleness of some plating, so your BCG stays protected whether you're running suppressed at the range, hunting in damp conditions, or pushing through demanding training. The complete package includes the bolt, carrier, gas key, firing pin, cam pin, and firing pin retaining pin—everything you need to drop into your upper receiver and start building.

Key Features

• Precision-machined 9310 steel bolt with heat treatment and shot peening for durability and consistency
• 8620 hardened steel carrier for sustained high-volume use
• Torqued and staked gas key installed to military specifications
• Extractor with rubber insert and spring for reliable case extraction
• Magnetic-particle inspected for internal and surface defect detection
• Black-nitride finish for corrosion resistance and longevity
• Complete assembly with all required pins and components

Specifications

Frequently Asked Questions

What cartridge does this bolt carrier group handle?

This BCG is specifically designed for 7.62x39mm rifles built on the AR-15/AR-308 platform. The bolt head is matched to the dimensions and pressures of the 7.62x39 cartridge.

What comes in the package?

The complete assembly includes the bolt, carrier, gas key (torqued and staked), firing pin, cam pin, and firing pin retaining pin. You receive everything needed to install into a compatible upper receiver.

Why does finish matter on a bolt carrier group?

The black-nitride finish resists corrosion and wear without the brittleness found in some hard-chrome or nickel alternatives. This coating protects your BCG through extended shooting sessions, suppressed fire, and adverse conditions while maintaining the smooth cycling you need for reliability.

What does magnetic-particle inspection mean?

MPI is a professional quality-control process that detects surface and near-surface defects in steel components that could affect reliability or safety. Every BCG in this batch has been inspected to catch imperfections that visual inspection alone would miss.