You will need to buy a rear sight kit. This includes the new sight blade and a new nut and windage screw.
The S&W sight is designed to be broken during disassembly. (No joke).
The windage screw has a weakened area that's designed to shear when the screw is stressed.
To change, run the sight all the way over to the left side. Then, using a well-fitting screwdriver, twist the screw until it shears. Note: The screwdriver MUST be a well fitting one.
Pull the old blade and the two pieces of the screw out, being sure not to loose the screw tension spring and plunder under the screw head.
Install the new blade and windage screw.
Attach the new windage screw nut, and resting the sight and screw head on a padded anvil, use a rounded-off center punch to carefully rivet the nut in place.
