Holding the rifle firmly in a padded vise, use a brass punch to remove the factory rear sight, left to right as viewed looking down the barrel. (Be careful not to mar or damage the barrel or wood)
Fill the exposed dovetail slot with a dovetail slot blank from our Accessories page.

Our dovetail blanks require just a bit of hand fitting to go into the dovetail. 

Every dovetail is different so this helps ensure a perfect fit!

A few strokes off the flat bottom of the blank and a little filing of one slope on the blank should allow you to insert it about 1/2 way before tapping it the rest of the way with your punch.