JP VMOS Bolt Carrier for .308

There's no such thing as "one size fits all" in AR operating systems. Tuning your rifle is the only way to realize its potential and provide the performance you want. In some rifles, a little tuning is the difference between reliable function and reliable frustration. JP offers more options in this department than any other manufacturer, because we have really thought it through and done the research.

Using the same weights as our Silent Captured Springs, the Variable Mass Operating System (VMOS™) enables mass tunability and improved buffering of your operating system for a much wider range of applications such as suppressed rifles or exotic caliber chamberings. Excess gas and higher fouling can easily push these rifles outside their operational window. The VMOS™ compensates for all factors, providing additional, reciprocating mass that ensures reliable function. Particularly in systems without an adjustable gas block, this level of control feels like liberation.

Like our other carriers, the VMOS™ models feature a 100% increase in bearing surface for smoother operation, improved alignment and lower wear. The longer cocking pad of our designs also contributes to optimal reliability. Exterior bearing surfaces are polished before the carrier then undergoes our state-of-the-art, multi-vendor QPQ (Quench-Polish-Quench) process. The final result is a rock-hard surface with remarkable natural lubricity for a ball bearing smooth function with proper lubrication.