Stick a magnet on it, if it sticks its steel, if not aluminum?
I tried the 9mm boxer primed ones. Got 2-5 loading and they split or get too loose primer pocket. So yes it can be done but not worth it.
^^^^^ This just buy some new brass and take care of it should last awhile
^^^^^ This just buy some new brass and take care of it should last awhile
I've seen them both Boxer and Berdan primed. With all the free brass cases on the range, I just leave the aluminum where it lay.



























