I just line the sight, on the empty revolver, up against the bottom edge of my workbench or desk top - and push and tilt the grip end up to pull the sight out, reversing the procedure to install the different sight. The fit should be tight or it will wobble. Some new sights will require 'fitting', ie, drawing over a fine stone, to properly fit the slot. If you go too far, the sight dovetail can be coated with blue Loctite, installed, excess wiped away, and left for 16+ hours to cure. You can break the blue Loctite's bond with heat - apply the tip of a 25W soldering pencil to the sight at the base for 10+ seconds, then push it against the workbench to remove. Excess sealant can be removed with acetone.