M14 Gas Block Instructions

Between the World War II-era .30 caliber M1 and the new generation M16 assault rifle introduced in Vietnam, there was the M14. The last of the large-caliber long rifles issued to the U.S. infantry, the 7.62 mm M14 was a hybrid of M1-style gas-operated action and more advanced fully-automatic fire capability. Gas from the discharge of the ammunition exits the barrel through a port leading to the gas block, consisting of a gas cylinder and piston. The gas pressure drives the piston rearward to operate the rotating bolt assembly, eject the spent cartridge and chamber the next cartridge. The M14 gas block requires little maintenance beyond periodic disassembly and cleaning. It is designed to operate without lubricant.

Things You'll Need

  • Gun cleaning solvent
  • M14 armorer's wrench
  • M14 gas system drill or #14 drill bit
  • Abrasive pad
  • Toothbrush
  • Thread lubricant
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Instructions

    • 1

      Unload the rifle and point it in a safe direction.

    • 2

      Unscrew and remove the gas plug at the forward end of the gas piston assembly using an M14 armorer's tool .

    • 3

      Place your hand over the open end of the gas cylinder. Point the barrel down and shake it gently. Catch the gas piston as it slides out of the gas cylinder.

    • 4

      Clean the gas piston and the inside of the gas cylinder with gun cleaning solvent. Use an abrasive pad or a toothbrush to scrub deposits from the outside of the gas piston. Clean deposits inside the bore of the piston with an M14 gas system drill or a standard #14 drill bit.

    • 5

      Insert the gas piston into the gas cylinder with the flat side of the piston towards the barrel.

    • 6

      Lubricate the threads of the gas cylinder plug lightly. Screw the gas cylinder plug into the gas cylinder and tighten with the M14 armorer's tool.