I deprime and clean brass before reloading and in some miscellaneous .45 brass I found an odd berdan primed what appears to be .45 case. Nothing I have will take picture close up. The base has the following numbers and letters: clockwise from a vertical 57 at 3:00,a horizontal I at 6:00, a vertical 1 at 9:00, and a horizontal SF at 12:00. No big deal just curious what it could be. can anyone help?