thanks guys......
i've used 3 brandnew bushmaster mags. the same problem, empty chamber bolt not locking at the lastround. i've tried the mags to my other brandnew armalite ar, its locking back with these mags. by the way, i'm using a eagle arms lower complete lower from wolverine. if only this is a 1911, the slide stop or the mag is the culprit. thanks for all your info, i'll try lube the bolt catch or maybe try to use and different lower receiver.