went down that route a few years ago used 55 g full lead heads with bullseye both gas checked and not ,key holed at 30 yards so gave up as a bad idea but mine was a 1 in 12 twist ,some ranges have different rules ,indoor the one i went to was passed up to 45 ,pistol cal carbines but there are some restrictions on the type of heads you use cant remember but i seem to think jacketed/ball or hollow point whernt accepted as target loads from a cntr fire rifle on indoor range