This cartridge is just over 1 1/2 inches long, the I.D. at the neck is approx. 7.35mm & has a very unsual rim. Stamped on the head, if I am reading it correctly, is RVA8-157 MK2A4 3-54. The brass is very heavy, any ideas what this is?
http://i92.photobucket.com/albums/l6/rldar/rva8.jpg
http://i92.photobucket.com/albums/l6/rldar/rva81.jpg