I've had several KJW handguns, and they've all been the metal lowers, not the cansoft smoked frames. I don't think they're aluminum or have steel internals, but all the same, they DO hold up incredibly well. Never had a problem with broken frames or much of an issue with internals breaking. I blew up a nozzle on my M9 before, but thats because I jammed a few BBs in the chamber and the CO2 had nowhere else to go.
