JPBC-4 : LOW MASS BOLT CARRIER FOR LARGE FRAME, 416 STAINLESS WITH QPQ

JP Low Mass Operating System

For the no-compromise competition rifle, our Low Mass Operating System (LMOST) offers the most significant improvement in the felt impulse of the rifle compared to any modification other than the addition of a compensator. By reducing the reciprocating mass within the operating system, the bolt velocity is increased while simultaneously reducing the overall impulse experienced by the shooter with each shot. Consequently, LMOST equipped rifles have virtually no reciprocating mass feel and move less during cycling, allowing for much faster sight recovery and follow-up shots.

While use of the LMOST components is recommended only for competition and sporting use, this is only precautionary as their reliability is excellent, particularly on rifles with adjustable gas systems. Like all our bolt carrier designs, LMOST carriers feature a 100% increase in bearing surface for smoother operation, improved alignment and lower wear in the upper receiver as well as the longer Mil-spec. cocking pad for optimal reliability. In fact, Team JP shooters have been using the LMOST system for over a decade without any reported operating system malfunctions at a match, and most every shooter that implements this operating system feel that it is proven to be a great performance improvement. Some shooters have even reported fewer unexplained flyers in their groups after switching to the LMOST system.

For small-frame rifles, the complete JP LMOST system consists of one of our low mass bolt carriers and our lightweight buffer conversion kit, but any LMOST component can be installed individually in your existing setup and run smoothly. Click on the tabs above to see more about the different LMOST carrier models we offer.

• Large-Frame (.308)
• Stainless Steel
• QPQ Black Finish

Requires DPMS-pattern bolt, firing pin and cam pin.

Weight: 10.82 oz. with key installed.

Compatibility

This notice pertains to any rifle based on the large-format AR-10-type or LR-308 platform typically chambered in .308 Winchester, 7.62x51 NATO or other cartridges requiring the longer magazine format.

Be aware that these receiver platforms are not standardized like the AR-15/M16 platform for which most parts are cross-compatible. Before ordering accessories and parts for your large-format rifle, make sure the parts are compatible with your particular platform. This bolt carrier is compatible only with the DPMS family of AR-10 products.

With the Armalite/Rock River family of large-frame receivers, this carrier can only be used as a complete bolt carrier assembly group with a DPMS-pattern bolt such as our .308 JP EnhancedBolt. Interchanging individual components will result in an unsafe configuration. Do Not under any circumstances mix and match components between the platforms.

Made in the USA