First - unload the gun, then check it again.
2. Clamp the gun barrel in some sort of non-marking vise (wood blocks or Brownells inserts).
3. Drive out the pin with a cup point 0.050" pin punch (left to right viewed from rear). Remove the old sight and clean the slot.
4. With a file, fit the new sight tab as a tight fit in the slot. Coat tab with red Lock-Tite, press into slot, and clamp until Lock-Tite hardens. Be sure to wipe off excess LT.
5. Using a #54 wire drill, use the pin hole in the sight base as a guide to drill half-way through the sight tab. Keep the drill perpendicular to the tab and try to avoid wallowing out the hole in the sight base.
6. Repeat #5 from the other side. Then clean up the hole so the pin will fit.
7. Apply red lock-Tite to the pin and carefully drive it into the hole from right to left. Clean up the excess.
Lock-Tite will help keep the pin and blade in place. If you ever need to replace the sight again, it will loosen with the force applied to the pin punch and blade as described in #3. Some people try to mark the blade and then drill the hole outside the gun. It can be done, but it requires great precision to get everything to line up. What I described is easier.
Buck
