First what do you mean by peened in place. Normally these were seated in a tapered dovetail cut in the receiver. You might check for a screw added to help retain a loose sight. This is fairly common and is located in the sight base. It was screwed in until it's contact with the bottom of the dovetail tightened things up. May be a hex head set screw down in a hole.. In either case check that no screw is holding it in place.. Dovetail sights are inserted from right to left, so must be removed from left to right!.. I clamp the difficult ones in a leather padded vise(the receiver) and using a polished steel punch and a ball peen hammer drive the sight out from left to right. If there are peening marks then someone had loose sight problems before and their ministrations are probably the cause of the rear sights breaking. Since yours sight is already toast, I would take a hack saw and cut a verticle slot thru the sight dovetail from top to bottom. You don't have to cut completely thru and be careful to not damage the dovetail cut in the receiver. More than one cut may be made and they will loosen the frozen in place dovetail. As I said before there should be no peening marks on the receiver..if there are they should be removed if possible. Also to aid the remove of a dovetail frozen in place, freeze the receiver in the deep freezer for several hours or overnight. This will shrink the steel releasing some of the pressure on the dovetail.. Dry ice or liquid nitrogen can also help. Be careful with the liquid Nitrogen as it is cold enough to make steel brittle. Let us know how it goes or should you need more help...
