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

Mein 2026Worldenglish 1
Mein 2026Worldenglish 1

Mein Reaches Super Final as Team Federal Cleans Up in San Antonio

Derrick Mein finished third in the Main Event and Gregg Wolf won American Field HOA at the 2026 World English Sporting Clays Championship.

Vincent Hancock Receives NRA Golden Bullseye Competitor Award in Houston

Four-time Olympic skeet gold medalist Vincent Hancock accepts 2026 NRA Media Golden Bullseye Competitor award at NRA Annual Meetings & Exhibits in Houston, Texas.

Results: 2026 Tennessee State BB Gun Championship

Lily Cope scored 474.9 of 536 to win the Tennessee State BB Gun Championship Match over 37 competitors in Cookeville.

Ohio State Captures 2026 Intercollegiate Pistol Crown as NRA Returns to the Range

Ohio State steamrolled the field at the 2026 Intercollegiate Pistol Championship in Missouri marking the NRA’s return to college pistol after seven years.

New: Steiner eDiscovery 10x42 mm Binoculars with Integrated 4K Camera

Steiner’s eDiscovery 10x42 mm pairs premium analog binoculars with an integrated 4K camera, robust internal storage and live streaming capability.

Oliver Wins World English Sporting Clays Championship in Super Final Comeback

Team Remington’s Braxton Oliver rallies from second place in the Super Final to win 2026 World English Sporting Clays Championship Main Event HOA title.

Interests



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