• Extended forward assist serrations and dust cover notch
  • More reliable operation
  • Polished surfaces


  • Caliber: 5.56 NATO / .223 Rem. / 300BLK
  • Weight:
    • FMOS Bolt Carrier: 8.82 oz.
    • Enhanced Bolt Assembly: 2.1 oz.
  • Finish:
    • Bolt Carrier: QPQ Black
    • Enhanced Bolt: Chromium Nitride
  • Material:
    • Bolt Carrier: Stainless Steel
    • Enhanced Bolt: SAE 9310 Steel
  • Profile: Semi-Auto


  • AR-15


  • FMOS Bolt Carrier
    • FMOS bolt carrier with gas key installed


The JP Enterprises Full Mass Operating System (FMOS) is a superior quality replacement bolt carrier for AR platform rifles. The engineering and design poured into the remake of the AR bolt carrier give you a component that doesn’t simply replace your old Mil-Spec bolt carrier but surpasses it in performance by leaps and bounds. While the JP Full Mass Bolt Carrier remains a drop in replacement, it is easier to clean than the original Mil-spec carrier furnished with your AR and improves accuracy.

Why JP Enterprises BCG?

The JP Full Mass Bolt Carrier features a 100% increase in bearing surface over Mil-Spec carriers and all of the sharp corners you see on Mil-Spec carriers have been radiused in JP Enterprises' redesign. The QPQ finished surface offers excellent lubricity and superior hardness. This allows for smooth operation and reduced wear to both the carrier and your upper receiver. The bore of this carrier is roller-burnished for a drag free finish that will not crack and peel like the chrome on standard Mil-spec carrier bores.

This JP Bolt Carriers are available as small frame bolt carriers for the .223 as a stand-alone stainless steel bolt carrier or as a complete carrier group including the JP Enhanced Bolt assembly.

All JP Enterprises components are proudly manufactured by American tradesmen of superior quality materials with the competitive marksman in mind.

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