Preview: JP Variable Mass Operating System

by
posted on October 19, 2016
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
vmos-a.jpg
JP Enterprises new Variable Mass Operating System (VMOS) bolt carrier enables rifles to be easily tuned for a wider range of applications, such as suppressed rifles or exotic calibers.

"There's no such thing as 'one size fits all' in AR operating systems," states JP founder John Paul. "Tuning your rifle is the only way to realize its potential and provide the performance you want. That's why we pioneered the adjustable gas block concept more than two decades ago. Tuning can be the difference between reliable function and reliable frustration."
null
JP says, "The VMOS bolt carrier ensures reliable function, especially for systems without an adjustable gas block."

Like JP's other carriers, the VMOS models increase bearing surface. The cocking pad is longer, and exterior bearing surfaces are polished before the carrier undergoes a multi-vendor QPQ (Quench-Polish-Quench) process.

The VMOS is available now for large-frame (.308) AR-type rifles starting at $319.95. This standard version of the large-frame VMOS carrier includes three steel weights. Two weights can be exchanged for heavier tungsten ones. JP plans to release a small frame (.223) version early next year.

Latest

Lapua Biathlon 2026 2
Lapua Biathlon 2026 2

Lapua Renews as Official Ammunition Supplier of U.S. Biathlon Ahead of New Olympic Cycle

Lapua has renewed its partnership with U.S. Biathlon as the organization’s official ammunition supplier for the upcoming Olympic cycle.

ATA Grand American Returns to Sparta With a Full Event Lineup

The Amateur Trapshooting Association’s 127th Grand American runs July 29 through August 8 in Sparta, Illinois, with a tribute to the late Lynn Gipson.

Team Winchester and Team White Flyer Stack the Podium at 2026 World English

Team Winchester and Team White Flyer shooters earned multiple podiums at the 2026 World English Sporting Clays Championship.

From Milestones to Movement: Inside USPSA’s 2026 Blueprint

Alan Turner outlines USPSA’s 2026 priorities: club recruitment rewards, mobile app upgrades, junior memberships and championship planning.

Derrick Mein Secures Silver at ISSF World Cup Shotgun in Kazakhstan

Team Federal’s Mein took silver at the ISSF World Cup in Almaty after Turkey’s Tolga Tuncer set a world record to take gold.

USPSA Limited 10: The Same Foundation, One New Option

USPSA Limited 10 now allows optics, but doesn’t require them. Same scoring, same equipment rules, same division. One change, one new pathway.

Interests



Get the best of Shooting Sports USA delivered to your inbox.