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Like our small-frame JPBC-1, this carrier is the ultimate game gun operating system, now available for your heavy metal rig. The JPBC-8 offers an extremely light recoil impulse with minimal sacrifice in reliability.

The JPBC-8 also pulls from the advances of our JPBC-7 Variable Mass Carrier. This standard version of the aluminum large-frame VMOS™ carrier includes three steel weights, two of which can be exchanged for heavier tungsten weights.

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

Package includes carrier, titanium firing pin, and instruction sheet.


  • Enhanced tunability of operating system
  • Faster sight recovery and follow-up shots
  • Increased bearing surfaces for slower wear and longer component life
  • Longer Mil-spec cocking pad for optimal reliability
  • Included Enhanced Gas Ring provides perfect bore-to-gas seal fitment and minimized friction/carrier wear
  • Included titanium firing pin eliminates possibility of slamfires at higher bolt velocities
  • Full-length forward assist serrations


  • Platform: Large frame (.308)
  • Material: T6 7075 Aluminum
  • Finish: Hardcoat anodizing
  • Configuration: Standard (3 steel weights)
  • Weight: 7.1 oz. (with carrier key)

Compatibility and Usage:

Non-ferrous specialty carriers should be considered consumable rather than lifetime parts. The JPBC-8 yields a performance advantage for competition applications at a price. Your usage and maintenance will determine the duty life of your carrier. Frequent and generous oiling will extend lifespan.

The JPBC-8 is a competition/race gun part only and is not recommended for any duty/defense use where absolute reliability is required. This carrier is also not recommended for SBR or suppressor use.

This carrier should also be run with an adjustable gas system to minimize stress on the entire bolt carrier assembly.

The large-frame VMOS™ carrier uses the same steel and tungsten weights as GEN 2 Silent Captured Spring units. Only the forward two masses are reconfigurable. The rear-most steel mass cannot be exchanged. This carrier should not be run stripped (i.e., without any masses).

This carrier will not cycle with a standard buffer retainer plunger installed. Standard buffer/spring components must be installed "loose" or replaced with a Silent Captured Spring. Because our Law Tactical Folder Silent Captured Springs require use of a buffer retainer plunger to work, they are also not compatible with this VMOS™ bolt carrier.


This carrier is not recommended for use with gas systems shorter than mid-length for longest service life. Use with carbine or shorter gas systems may result in gas erosion in the tail stock area and subsequent leakage and reduced service life.

To help avoid the instance of slamfires, this bolt carrier comes packaged with a titanium firing pin. We strongly encourage use of a titanium firing pin with this carrier to ensure safety.

Use of a hammer with a radiused leading edge such as our JP Speed Hammer is recommended.

Use with a Silent Captured Spring assembled with a lighter weight spring will produce superior results.


Patents: 10,184,739
Product Instructions

Price: $315.00