ask me y I've bought replacement sears before....I haven't actually destroyed a sear but was in fear of it while learning...ordered couple Wilson bullet proof and they do need fitting cause they r made bigger than necessary...they have a 36 tho. face up against 20 tho. hammer hooks and the safety bar contact area needs to b filed down to engage ur safety. they also sell a regular sear thats drop in as well... Midway has them and others make really good drop in's that r the right fit. I spent a lot of time on my Wilson Bullet Proof sear in my Rock Isl. 9mm and got it down to 2 lb. 12 ozs....don't want that for every gun thou