I am using 348 Win brass that has been trimmed and formed with a 10.4x47R FL size die. 8mm Lebel brass also works. I use bullets from a dedicated heeled mold by RCBS which is no longer made. Slug your bore; you may be able to use 44 caliber bullets. I've not done that but a fellow forum member has and may post directions. It keys on bore diameter, though. SW