United Defense Manufacturing Corporation undertook the development of the rifle as a possible replacement for traditional AR-15 designs.
[citation needed] The PVAR system was designed in an attempt to reduce malfunctions by preventing the buildup of heat, lead and copper fouling inside the receiver by utilizing mechanical energy instead of the pressurized gases of the cartridge to cycle the bolt, the process by which a round of ammunition is fired, ejected, and a new round is loaded.
The manufacturer advertises that the PVAR system reduces the need for field maintenance and overall wear and tear compared to the standard AR-15 design.
Unlike many gas piston systems, the PVAR features a free-floating piston rod that, upon firing, travels rearward and essentially increases the mass of the bolt carrier group during most of the firing cycle in order to reduce recoil.
PVAR rifles are installed with one-piece free-floated M1913 quad rail handguards made of 7075-T6 aluminum mounted on a matching proprietary barrel nut.