How many times have I heard what shall I do when a builder accidentally files too much from the sight slot and the slot is loose in the dove tail? Hundreds I guess. The standard fixes are solder in the slot. Punch marks in the barrel, Loktite and so on which never really do a very good job of tightening up the dovetail. Well here is one that really works and it will stay as good as if should have originally. Nobody will ever be able to tell it was ever loose.
Place the sight blade upside down in between the vise jaws. Don't put too much pressure on the blade so as not to scar it up. Now take a small hammer and pound on the sight base. It is best to use a cross peen hammer so as to spread the sight base in length. This will thin the base but very slightly. It will also lengthen the base and make it fit tight in the dove tail. Nobody will ever know. Have fun