JP Enterprises VMOS Variable Mass AR-15 Bolt Carrier 5.56x45mm NATO QPQ Black

For difficult setups like suppressed rifles and exotic caliber chamberings, some degree of mass regulation is required for optimal performance. This is especially true in the absence of an adjustable gas block. Residual gas and excessive fouling can grind your rifle to a stop. One size never fits all when it comes to gas-operated rifles. The Variable Mass Operating System (VMOS) carrier ensures reliability through additional reciprocating mass but provides more custom tunability. Combined with t