UDMC S5:F5 Caliber 5.56 NATO Rifles

UDMC S5/F5 Caliber 5.56 NATO Rifles

October 14, 2020
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UDMC S5/F5 Caliber 5.56 NATO Rifles

  • Bergara SS-410 Barrel for commercial models
  • UDMC 4150 Barrel for military specification models
  • Two Platforms: PVAR Gas Piston or DGIS Direct Impingement

United Defense Mfg Corp’s F5-PVAR, S5-PVAR, F5-DGIS and S5-DGIS rifles are variants of the M16 and M4 rifles and come in two types: The “F-series” are the military full automatic models. “S-series” are the semi-automatic models. These rifles are chambered in the time-tested 5.56 NATO round (5.56 x 45mm) and designed to hit point targets up to 600 meters (MER) with the use of a 14.5-inch barrel. The F5 and S5 series take after the M4 and M16 battle rifles designed by Eugene Stoner. They use two different action designs, the Direct Gas Impingement System (DGIS) and the patented Pneumatic Valve and Rod (PVAR) system. The DGIS is the simpler design between the two as it has less parts and uses the hot gases coming from the gas port of the barrel and through a gas tube the hot gases are rammed into the bolt carrier group to cycle the round.

On the other hand, the Pneumatic Valve and Rod (PVAR) gas-piston or simply the patented PVAR™ system or Pneumatic Valve and Rod System is a “bare bones”, no frills and very simple designed gas and piston operating system that utilizes a combination of gas and mechanical energy for a more effective and reliable cycling of the weapon. The PVAR design prevents hot and high-pressured gases from reaching the bolt assembly. This results in a cleaner and reliable operation, as well as minimal maintenance even in the most rugged environments such as jungles, deserts, snow and salt-water conditions. This means reduced cleaning time and overall longer rifle life span.

The PVAR’s simplified parts and mechanism allows reduced recoil and reduced muzzle rise, which enables the shooter to refocus instantly on the target for each and every round fired! The DGIS uses a lightweight thermoplastic handguard and the PVAR uses a one-piece keymod rail handguard with a military standard 1913 Picatinny top rail held securely only at the barrel extension which allows the barrel to “float” and reduce barrel vibration while in battery. This allows for greater accuracy and consistency. As designed, the barrel does not touch any part of the entire length of the handguard except at the barrel extension. The barrel comes in different lengths: 7.5, 10.5, 11.5, 13, 14.5, 16, 18, 20 and 22 inches.

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