How to Assemble AR15 Forward Assist

AR15-style rifles are semi-automatic weapons built on the platform of the military M16 assault rifle. Early testing of M16 prototypes revealed reliability issues in a combat environment. Dirt, grit and/or excess carbon accumulation in the chamber could prevent the bolt from moving fully forward to the locked position. The forward assist button was developed as a manual means to quickly force the bolt into the closed position. Depressing the spring-loaded forward assist actuates a plunger, which engages ridges on the bolt carrier to manually push it forward and chamber the round. At the behest of the U.S. military, the forward assist button was added to the standard-issue M16 design beginning in 1964.

Things You'll Need

  • AR15 vise block
  • Bench vise
  • Number 3 pin punch
  • Ball peen hammer
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Instructions

    • 1

      Separate the upper receiver from the lower receiver.

    • 2

      Place the upper receiver in an AR15 vise block. Turn the receiver upside down and tighten it in a vise.

    • 3

      Slip the forward assist spring over the forward assist plunger rod.

    • 4

      Place the plunger rod and spring into the forward assist guide hole. Orient the hook on the pawl of the plunger rod so it is facing toward the body of the receiver.

    • 5

      Depress the plunger rod all the way in and hold it in the depressed position.

    • 6

      Place the forward assist retaining pin in the pin hole.

    • 7

      Tap the pin in using the number 3 pin punch and a small hammer. The pin should be tapped in until it is just below the surface of the forward assist.

    • 8

      Test the forward assist by pressing it all the way in and verify that it springs completely back out.

    • 9

      Remove the AR15 vise block from the vise and remove the upper receiver from the vise block.

    • 10

      Re-install the upper receiver on the lower receiver.