Full Mass Operating System For police duty or any application where absolute reliability is the main criteria, our 416 stainless steel Full Mass Operating System (FMOS) carrier design is the top of the line. The JPBC-2 has every strength an operator expects from a Mil-spec. carrier matched up with improvements born from decades of shooting and engineering experience. Heavier than a standard .308 carrier, our large-frame JPBC-5 is the solution for rifle needing more mass regulation. Designed with extended forward assist serrations and a dust cover notch, our FMOS carriers also feature a 100% increase in bearing surface for smoother operation, improved alignment and lower wear in the upper receiver as well as a longer Mil-spec. cocking pad for optimal reliability. Just as critical as the design is the robust finishing process of the FMOS carrier, which receives a roller-burnish of its bore for frictionless operation, eliminating the peeling chrome common to standard Mil-spec carriers. Then, the exterior bearing surfaces are polished before the carrier undergoes our state-of-the-art, multi-vendor QPQ (Quench-Polish-Quench) process that results in a rock-hard surface with remarkable natural lubricity. This is hands-down the best designed and highest quality general purpose carrier on the market, and when properly lubricated, a JP operating system will make your rifle feel like it’s cycling on ball bearings. JP Low Mass Operating System For the no-compromise competition rifle, our Low Mass Operating System (LMOS) 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, LMOS 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 LMOS 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, LMOS 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 LMOS 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 LMOS system. For small-frame rifles, the complete JP LMOS system consists of one of our low mass bolt carriers and our lightweight buffer conversion kit, but any LMOS component can be installed individually in your existing setup and run smoothly. Specifications for JP Enterprises Complete JPBC Bolt Carrier Group (BCG): Manufacturer: JP Enterprises Fabric/Material: Stainless Steel Cartridge: .308 Winchester Gun Model: AR-10 Gun Frame Size: Large Hand: Right Condition: New Bolt Material: 9310 Steel Carrier Material: 8620 Steel Caliber: .308 Caliber Package Contents: JP Enterprises Complete JPBC Bolt Carrier Group
Kenny –
My second Bcg from Jp and definitely not my last. I purchased an JP polished Enhanced bolt assembly with an .308 high pressure bolt and it's what I always expect from JP enterprise. An lightweight, tunable, high pressure BCG for my 6.5 Creedmoor build. It not just an JP BCG assembly. If you have the time do some research on JP's BCG's. Its totally tunable and every part on the assembly was not overlooked. From the cam pin to the gas ring, extractor, firing pin etc. JP took the time to enhanced just about everything on there large frame LMOS carriers.
Aaron Green –
When building for light weight the only carrier I found that was lighter than this one is from V Seven however in todays stocking crisis I couldn't find one. I emailed JP Enterprises and ask about ship times they recommended coming to Optics Planet as they had orders in already being filled. The carrier shipped way faster than the expected ship date (2 months faster). The part numbers are a little confusing when trying to order the complete BCG with bolt and firing pin so pay attention. That being I said I reached out to support via chat and as always the representative was very knowledgeable and made sure I ordered exactly what I was looking for.
Ray –
Great piece of kit. Super smooth and reliable. The coating is perfect and uniform, this has been 100% reliable for me. This really took my .308 to the next level. It cut down on recoil quite a bit. The adjustable buffer can be added but I didn't, this works perfectly fine without it.
Rich –
Yes, its very expensive, but without a doubt it is the smoothest bolt carrier I have ever felt. It runs great in my Aero M5 build. It cleans pretty easily if your into that kinda thing. JP really is a step above most. The quality control is amazing, they are quite helpful with questions and other help. Its a pricey bolt but I certainly don't feel I overpaid. The quality is all there.
Ryan –
It's a good deal of money, the most expensive part of an AR-10 build, but if accuracy matters, this is what you need to buy. Also, the coating on it is incredible, you can clean it with a tissue if you desired.
Ryan –
This is what you want for accuracy. Little known, JP bolt is what standard headspacing for AR10 barrels are set off of. It does weight more, but it allows you to shoot heavier bullets at higher velocities