I'm not a reloader. Someday, but not today. Steel cases, I will not use. (Personal preference i guess). Steel is for AKs. But what about aluminum cases? I believe I read aluminum is cheaper then brass(a given) also NOT reloadable. For my situation, not a problem. What are the negatives of using aluminum? I'm very picky about my firearms. I've purchased a used Kimber 45 from a friend, one box of(50) steel case through it left its share of marks behind(I was there). Why I won't use steel. So that brings up the aluminum question.. I've heard, aluminum is way softer then brass,(agreed) but also leaves more deposits behind as a consequence?? Creating issues if not addressed correctly?? Anyone wish to share some TRUTH? I'm sure all will run, but I'm not a beat up my firearms kinda person. Don't get me wrong, I'll run the crap out my firearms, but I appreciate what I have too..