How to Install an HK Buffer

Heckler & Koch GmbH is a German manufacturer of small firearms. The company's iconic G3 assault rifle has equipped a number of NATO military forces since its introduction in 1959. A "civilianized" version of the weapon, the HK91, was available in the United States from 1979 to 1989, and licensed third-party versions are still available on the civilian market. The weapon's buffer is mounted inside the back plate and helps secure the butt stock to the recoil assembly. The installation of a new buffer -- whether as a repair or as part of an upgrade -- takes about an hour.

Things You'll Need

  • Padded gun vise
  • Gunsmith's drift pin
  • Mallet
  • Phillips screwdriver
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Instructions

    • 1

      Press the magazine release, located on the left side of magazine well, and remove the magazine from the weapon. Pull back on the cocking lever, located on the right side of the receiver, to eject any chambered ammunition. Look through the ejection port to visually verify that the weapon is unloaded.

    • 2

      Secure the rifle in a gun vise with the butt stock slightly elevated to provide good working access.

    • 3

      Locate the butt stock locking pins on the rear lower receiver. Drift out both pins from right to left with your pin punch. Pull the back plate and butt stock assemblies backward out of the receiver and pull them free from the rifle.

    • 4

      Look through the front of the back plate to locate the two self-locking screws that attach the buffer to the butt stock. Remove both screws with a Phillips screwdriver, then separate the back plate from the butt stock.

    • 5

      Grip the back plate in one hand and press firmly on the rear of the buffer to loosen it. Push the buffer out the front of the back plate and set it aside.

    • 6

      Slide the new buffer into the back plate. Make sure the flat side of the buffer faces the front.

    • 7

      Insert the butt stock into the rear of the back plate. Push the buffer into place until it seats firmly against the rear of the back plate. Insert the two self-locking screws through the holes in the buffer and tighten them down with a Phillips screwdriver.

    • 8

      Slide the back plate and butt stock assembly into the rear of the rifle's receiver. Take care to make sure the recoil spring, which extends from the top of the back plate, seats properly into the upper receiver.

    • 9

      Drift in the butt stock retaining pins from left to right to reattach the back plate and butt stock assembly to the rifle.