I use WW296,WW brass,Sierra 45 gr bullets(#1210) w/Rem 6 1/2 primers.This is for a Ruger 77/22 Hornet w/20" barrel.I don't know if i was loading to hot(10.5grs,book shows 12.4 as max)or like Sierra suggusted,maybe old brass?but i started getting case sepperations(brass neck sized only,NOT...