I have a piece of brass a friend's little boy picked up at the range the other day and I can't figure out what it is. It uses a .308 diameter bullets, is 2.185 inches long and is berdan primed. The rim is similiar to a .308 (30-06, 45 ACP, etc.) only larger. Appears to have had a heavy military style crimp. on the headstamp at 12:00 it has the number "10", at 3:00 it has the letter "A", at 6:00 it has the number "82" and at 9:00 it has the letter "D". Seems to have a larger powder capacity than a .308 Winchester.