How to Remove a DPMS Gas Block

DPMS manufactures a line of civilian AR-15-style semi-automatic rifles in calibers ranging from .204 Remington to 7.62 mm NATO. All rifles built on the AR-15/M-16 platform feature a gas block near the end of the barrel that channels gas pressure from the discharge into the gas tube and back to the receiver. This gas pressure operates the rifle's ejection and auto-loading mechanism. The gas block is incorporated into the base of the AR-15's one-piece front sight post. Removing the gas block is a universal procedure on all AR-15-style rifles, in order to replace or remove the front sight, as when adding a scope or enhanced sight, or to install an after-market barrel.

Things You'll Need

  • AR-15 taper pin punch
  • AR-15 vise block
  • Hammer
  • Plastic hammer or wooden mallet
  • Penetrating oil
  • Wood block
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Instructions

    • 1

      Make sure the rifle is not loaded. Remove the magazine, open the bolt and visually verify that no rounds are present in the chamber.

    • 2

      Unscrew the flash suppressor and remove it from the end of the barrel.

    • 3

      Press the front and rear takedown pins in the receiver and separate the upper receiver from the lower receiver.

    • 4

      Soak the two taper pins that secure the base of the front sight/gas-block assembly with penetrating oil.

    • 5

      Lay the upper receiver and barrel assembly on its right side on a firm surface with a block of wood beneath the gas block. Use shims if necessary to make sure the barrel and receiver are supported equally along the entire length of the rifle.

    • 6

      Position the AR-15 taper pin punch on the rounded end of one of the two gas block taper pins, holding the punch vertical to the pin.

    • 7

      Strike the punch firmly with a single hammer blow to break the pin free and start the pin in motion. Reduce your striking force with subsequent blows as you drive the pin slowly out from the right side to the left side of the gas block.

    • 8

      Repeat the procedure on the other gas-block taper pin.

    • 9

      Install the upper receiver in an AR-15 vise block. Tighten the vise block in a bench vise with the barrel extending horizontally.

    • 10

      Gently tap the front sight/gas-block assembly from side to side using a plastic mallet against a block of wood to loosen it on the barrel. Then tap it forward toward the muzzle, separating the other end of the gas tube from its joint at the receiver in the process. Once it clears the larger diameter of its mounting surface on the barrel, the gas-block assembly can be easily slid forward by hand and off the end of the barrel.