How to Install KNS Precision Non-Rotating Trigger and Hammer Pins

Two press-fit pins secure the trigger/hammer assembly inside the lower receiver of an AR15-style semi-automatic rifle. Vibration from shooting may cause these pins to rotate in their mounting holes. Over time, wear from this motion can enlarge the holes significantly. Loosened trigger/hammer pins may eventually "walk" out of the hole entirely, resulting in failure of the trigger assembly. Once the mounting holes have been enlarged by wear, over-sized pins must be installed and the receiver machined to accept them. KNS non-rotating pins replace the OEM pins before excess wear and walking occurs.

Things You'll Need

  • Small metal pin punch
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Instructions

    • 1

      Screw the pointed brass installation tool onto the end of the internally-threaded replacement trigger pin.

    • 2

      Press the pointed tip of the installation tool against the end of the trigger pin on the lower receiver just above the trigger housing. Push the existing trigger pin out with the installation tool while simultaneously feeding the replacement trigger pin in behind it. When the replacement pin is fully installed and flush with the surface of the lower receiver, unscrew the installation tool.

    • 3

      Push the existing hammer pin out approximately 1/8-inch with a metal pin punch. Use the replacement hammer pin to continue pushing the existing hammer pin out until the replacement pin is fully installed with the tabs on each end protruding slightly from the surface of the lower receiver.

    • 4

      Fit one end of each connector link over the tab on the end of each hammer pin on both sides of the receiver. Align the hole in the other end of the connector links with the threaded hole in the end of the trigger pin on both sides of the receiver. Secure the connector links to the threaded trigger links with the hex screws and supplied hex key wrench.