MPN: 111-001


  • Lighter for less felt recoil
  • Strong, easy-to-clean, enhanced heat treated Blackntride+ finish inside and out
  • Revolutionary treatment eliminating the need for excessive oil or grease on tactical components
  • Synthetic fluoropolymer of tetrafluoroethylene to each part to reduce friction and improve wear
  • Precision machined bolt
  • Gas key is properly staked
  • Made in the U.S.A.


  • Caliber: 5.56 NATO / .223 Rem. / 300BLK
  • Weight: 9.1 oz.
  • Finish: Blacknitride+
  • Material:
    • Carrier: 8620 Steel
    • Bolt: 9310 Steel
  • Profile: Low Mass


  • AR-15


  • 1x Steel Bolt Assembly
  • 1x Extractor
  • 1x Cam Pin
  • 1x Low Mass Steel Bolt Carrier
  • 1x Carrier Gas Key
  • 1x Firing Pin
  • 1x Firing Pin Retaining Pin


The bolt carrier group moves back and forth with every shot. By reducing its weight, you reduce the weapon's felt recoil. Rubber City Armory's lightweight BCG, at 9.1 ounces, is the ideal bolt carrier group for the competition shooter who wants to construct a lighter AR-15 rifle with less recoil and quicker target acquisition. Compatible with all AR-15 systems, this Rubber City Low Mass BCG reduces the felt recoil of each shot, making it easier for you to reacquire the sight picture for a faster follow up shots.

What Materials Are Used to Build the Rubber City Armory's Lightweight BCG?

The bolt carrier group itself is constructed from 8620 steel and features cutouts to reduce weight. This steel is a composite alloy hardened by a process called carburization, which involves the reintroduction of carbon to further harden the steel. The entire low mass BCG is then given H&M’s Blacknitride+ finish.

What Is The H&M Blacknitride+ Finish?

The H&M Blacknitride+ finish is a thermochemical treatment not only hardens your steel, but also provides a corrosion resistant lubrication what both protects your weapon's metal and provides a slicker finish to facilitate speed, reduce fouling, and extend the life of your BCG.

Do I Need to Do Anything Else Beside Dropping This in My AR?

You can just drop this low mass bolt carrier group in your AR and it will work fine. However, you might get a thump in the shoulder due to the lighter weight and faster action. It is highly recommended to use an adjustable gas block or gas key to controls the gas flow. This will slow the movement of the bolt carrier group and lessens your recoil, making it easier for you to quickly reacquire the target.

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