This has to be the strangest problem I have ever had reloading. Last year I built a 6.5 Wby. (257 WBY necked up yo 6.5) The load developement went as you would expect, the Wby case liking loads on the warm side. It is shooting 140 bergers @ 3350 fps into less than a half inch at 100 yds. I put the rifle away for hunting season, and picked it up recently to do some more loading and took it out to the range with some of the handloads I had from last year. This is where it got interesting. The exact loads I was using last year are blowing the primers out now... Thinking I loaded too much powder I went back to my notes, no this is the load that shot well in my developement. Checked the powder, out of the same bottle, checked seating depth, same as last years, same primers too. Obviously I have to go back to the drawing board and start over with my load developement. My next move is to start with some fresh cases, and give the rifle a thorough cleading. Got any ideas why this is happed???? Or what to do?