The Aero Precision AR15 5.56 PRO Series Bolt Carrier Group in black nitride (brand part no. APRH101767C) is a bolt carrier group designed around service life. Aero Precision machines the bolt from 9310 steel and heat treats it with a proprietary flash nitride process, and the cam pin channel is counter bored rather than swaged. The cam pin carries an engraved indexing mark so it can be installed the same way every time, which helps limit uneven wear. The carrier is an M16 cut design with a nitride finish and precision-ground internal surfaces. For a shooter building or refreshing an AR-15 in 5.56, it is a complete group that arrives ready to install.

Key Specifications

• The chambering designation is 5.56 NATO, matching the AR-15 platform this PRO Series group is built for.
• The bolt is machined from 9310 steel and is shot peened and magnetic particle inspected, steps that go toward long bolt life.
• The cam pin is machined from 4140 steel with an engraved indexing mark, so it can be installed consistently during maintenance.
• The carrier is an M16 cut design with a nitride finish, with internal surfaces ground for gas efficiency.
• The gas key is hardened 4140 steel with grade 8 fasteners, staked to mil-spec, a joint that stays tight under use.

Frequently Asked Questions

What makes the PRO Series bolt different? It is machined from 9310 steel and heat treated with a proprietary flash nitride process, and its cam pin channel is counter bored instead of swaged, which Aero says avoids the stress that swaging adds.

Why does the cam pin have an indexing mark? The engraved mark lets you install the cam pin the same way each time. Cam pins tend to wear more on one side, and consistent installation reduces wear on both the pin and the bolt.

Buy the Aero Precision AR15 5.56 PRO Series Bolt Carrier Group, Black Nitride

A bolt carrier group sets how long an AR-15 runs between rebuilds, and this one is built with that in mind from the bolt to the gas key. Order it from our Lubbock, Texas gun shop for fast, direct shipping, and see more AR-15 accessories and parts to finish the build.