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 our Silent Captured Spring, multiple masses
are exchangeable to perfectly tune your operating system weight.
This standard version of the large-frame VMOS™ carrier includes three
steel weights, two of which can be exchanged for heavier tungsten
Package includes carrier and instruction sheet.
Requires DPMS-pattern bolt, firing pin and cam pin.
For a complete operating system, this carrier pairs best with the JPSCS2-10H2.
Weight: 16.0 oz. (as configured)
- Enhanced tunability of operating system
- Guaranteed reliability of difficult configurations
- Overcomes all fouling build-up
- Roller-burnished bore for frictionless operation
- Rock-hard QPQ finish provides remarkable natural lubricity
- Extremely smooth cycling with proper lubrication
- Increased bearing surfaces for slower wear and longer component life
- Longer cocking pad for optimal reliability
- American made
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
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.
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 bolt carrier group components will result in an unsafe
configuration. Do Not under any circumstances mix and match components
between the platforms. Only use DPMS pattern bolt, firing pin and cam pin with this bolt carrier.