The best of the FMJ M193 that I've found is IMI's 55 grain ammo; the MEN stuff from Germany is pretty good too.
The PMC Bronze .223 is decent, but generally not quite as good as IMI, if it will cycle reliably in your gun...............
The Norma Tac 55 is reputed by some to be pretty decent too, but I've not tried it but I will whenever I need to buy some more banging ammo.
Or if you really want to know what your gun can do, just buy some Federal GM 69 or 77 grain ammo, depending on your barrel twist; Hornady TAP & Match in whatever bullet weight you want, is pretty good too for factory ammo.
