I don't know anything about 1911's but I do know a thing or two about the AR-15. For that, you will need one of those multi-tool wrenches that has a spanner, a barrel nut and some other shapes on it. That will let you tighten and remove barrels and collapsible stocks. Probably some other uses for it also, but I only use it for those two. You'll also want upper and lower receiver vice blocks. This will keep you from damaging a reciever as it is clamped in a vise while working on it. After that, you'll want a good set of punches of various sizes to work with all the pins, also some good hex wrenches and gunsmithing screwdrivers. If you plan on mounting scopes, maybe pick up a scope lapping kit. That's about all I know.