I feel I got duped sort of, just picked up 450 rounds of 9mm Winchester and after leaving the store realized it is steel cased. I didn't realize a American ammo maker made steel cased, and on the box it had the word "brass" I didn't see above the word "steel" so I assumed it would be brass cased ammo. see photo. I also have a box of 100 pack Federal aluminum case .45 ACP ammo been holding on to. My questions are, just how hard on a gun is using steel cased handgun ammo , and for aluminum case ammo is there anything to beware of?