Installation of 57GPR on Lyman Great Plains Rifle

The Lyman Great Plains Rifle (made before April 1997) will require one hole to be drilled and tapped for the included 8/32 screw. Rifles made after April 1997 will have the hole drilled and tapped at the factory.
  1. Remove the slide from the sight base.
  2. Unscrew and remove the rear tang screw. The original rear tang screw will not be used.
  3. Place the included sight adapter block on the tang (still in stock) so that the thick end of the adapter block is at the rear of the tang and the angled front edge lines up with the angled front edge of the sight base.
  4. Place the sight base on the adapter block and attach it using the wood screw supplied with the adapter block. The screw is positioned in the rear hole and will pass through the sight base, adapter block and rifle's tang, and then is screwed into the stock.
  5. *Mark center of front hole on the tang and drill with a No. 29 drill (removing the tang and clamping it in a vise will protect the stock of the rifle during the drilling operation).
  6. *Tap hole for 8/32 thread.
  7. Secure sight base and adapter block to the tang with wood screw and the 8/32 x 1/2" machine screw that is supplied with the adapter block.
  8. Replace the slide.

Installation is complete.

* Not necessary on rifles that are drilled and tapped.