I bought an grab bag from a dealer, there was a ar 9 Lower. Spent two hours “drill press” milling one of the mag support to fit the mag release. Very slow and took my time. Finished with a router. Should of did the router the whole time. When went to test fit, found out I needed to cut a channel for where the pin goes for the glock style mag release
Went looking in a box, found another jig, it fit. Problem, lost all the top plate screws. Same goes with one I was adapting.
What a morning