I was given a RCBS JR2 press and have built a bench and have all the equipment I need to start reloading . The press was missing the plug to seat the primers off of the press and RCBS generously sent it to me free of charge .I put the plug ,spring and sleeve into the priming arm and am good to go .The first 2 brass I have tried to prime , I can't seat the primer below the bottom of the brass , just lacks a CH but is a little proud of the brass . I can lift the bench off the floor and still won't seat . Brass is clean and primer pocket cleaned out . Once fired 243 Hornady brass , Remington large rifle primers .Any suggestions ?