The Aero Precision APRH308184 is a complete .308 Win / 7.62x51mm NATO bolt carrier group built for AR-15 style M5 platform uppers. Whether you're assembling a precision rifle from the ground up or replacing a worn BCG, this is a no-compromise component engineered to handle the demands of full-power rifle shooting. Machined from quality steel with a hard-wearing black phosphate finish, it's the kind of part that lets you focus on your shooting instead of your gear.
The carrier itself is cut from 8620 tool steel and finished in black phosphate, with a gas key machined from 4130 steel and secured with Grade 8 hardware, properly staked. The bolt runs 9310 case-hardened steel with external surfaces CNC ground after heat treatment for a precision fit. The bolt has been magnetic particle inspected (MPI) and high-pressure tested (HPT) to catch any manufacturing defects before they reach you. A hard-chromed 8740 steel firing pin, dual-spring/dual-O-ring extractor from 4340 steel, cam pin, and retaining pin round out the assembly—everything you need to fire and cycle rounds downrange.
Thanks to its multi-caliber design, this bolt works not just with .308 Winchester and 7.62x51mm NATO, but also .338 Federal and other .308-based cartridges, giving you flexibility if your builds diversify. The precision-ground bolt and reduced .070" firing pin hole diameter reflect Aero's attention to detail. A laser-engraved Aero Precision logo marks it as quality American manufacturing.
| Caliber | .308 Win / 7.62x51mm NATO (multi-caliber: also .338 Federal and .308-based cartridges) |
| Platform | AR-15 style M5 upper receiver |
| Carrier Material | 8620 tool steel |
| Bolt Material | 9310 case-hardened steel |
| Finish | Black phosphate |
| Gas Key Material | 4130 steel (Grade 8 hardware, properly staked) |
| Firing Pin Material | 8740 steel, hard-chromed |
| Extractor Material | 4340 steel (dual springs, dual O-rings) |
| Inspection | Magnetic particle inspected (MPI) and high-pressure tested (HPT) |
| Includes | Bolt carrier, complete bolt, firing pin, cam pin, retaining pin |
Yes. The APRH308184 is designed for AR-15 style M5 platform .308 uppers and chambers. It also works with 7.62x51mm NATO, .338 Federal, and other .308-based cartridges thanks to its multi-caliber bolt design.
Magnetic Particle Inspection (MPI) and High-Pressure Testing (HPT) are quality-control processes that catch hidden defects in the steel before the bolt reaches you. They ensure reliability and safety—especially important in a component that sees the pressures of full-power rifle rounds.
The complete assembly includes the bolt carrier, a fully assembled bolt, firing pin, cam pin, and retaining pin. Everything you need to install and run in your upper receiver.
Heat treating steel changes its properties but can distort dimensions slightly. Aero grinds the external surfaces after heat treatment to restore precision tolerances and ensure a tight, reliable fit in your carrier and receiver.
AeroPrecision
AeroPrecision
