The American Built Arms Pro 5.56 Bolt Carrier Group is a mil-spec unit made for heavy use. Specially manufactured on specialized high-end Swiss machinery, these bolt carrier groups have precise tolerances and beautiful surface finish. Because of the special manufacturing process, the ABA Pro is made with exceptional quality at a very ordinary price.

When I opened the package containing the BCG, the first thing I noticed was its contrasting finishes. The carrier is coated with manganese phosphate, and the carrier is chrome-lined for extra lubricity. The bolt and cam pin are nickel-boron coated. This combination of coatings greatly reduces friction and requires minimal lube—even for prolonged use. The extractor has a phosphate finish because the friction from the rough surface provides more reliable extraction.


American Built Bolt Carrier Groups are ready to drop into your rifle, so that is exactly what I did. The headspace gauge said “go,” so off I went to the range. The bolt did not disappoint. After 500 rounds, the bolt was free from excessive carbon buildup and still functioned smoothly. I plan to put many more rounds downrange with it, and will write a full review after I have some more experience with it.

American Built Arms provides their high-quality bolts and extractors to some major-league rifle manufacturers. Quality components produce a quality rifle. You can get your bolt the same place the big boys do with the same great results.


Carpenter 158 Steel
Heat treated per mil-spec requirements
Shot-peened per mil-spec requirements
MPI-tested material
Nickel-boron coated

Bolt carrier:
8620 steel
Phosphate coated
Chrome-lined bore
M-16-style with more mass for better functioning in semi or full-auto rifles

Gas key:
4130 steel
Black nitride
Gas-key screws – 4140 steel properly staked per mil-spec requirements

Cam pin:
4340 steel
Heat treated per mil-spec requirements
Nickel-boron coated


Aircraft-quality E4140 steel
Heat treated per mil-spec requirements
Shot peened per mil-spec requirements
Manganese-phosphate coated per mil-spec requirements

Firing pin:
AISI 8740 steel
Chrome coated

Made in the USA!

American Built Arms Pro 5.56 Bolt Carrier Group – Nickel Boron Coated Bolt & Cam Pin – Phosphate and Chrome lined Carrier price: $189.99

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