I have been working with this mod 12 FV 22-250 since June and early on it seemed to prefer 55gr. to 50gr. bullets. So I thought I would try some 60 gr. if I could find them. A friend said he had some 50 gr. Nosler solid base I could have and if they work he had 400 more I could have. I first tried IMR4064, then another lot of 4064 then RL-15 and Win 760 and today IMR 4350. The loads all were the starting loads from 3 different manuls. With the 760 it shot good but when I went up .3 of a gr. it blew the primer on about the 3rd shot. Today I started with 34.5 gr. of Imr 4350 the starting load from the Nosler Reloading Data site. I checked the load on 2 balance beam scales and the cases had been trimmed exact, FL resized. The first shot from a cold barrel seemed good the primer had rounded edges, the 2nd shot also except the primer was a little flatter, the third shot the primer was flat and the bolt was stiff to open, the 4th shot blew the primer,the extractor and locked the bolt up to where I had to take a plastic hammer and drive it open, then use a cleaning rod to bump the case out. It has been doing this with 4 different bullets and the powders I named to different degrees.

I have been loading for 43 years and for about 12 or 14 different 22-250s I have always had 1 or 2. I load for 24 different calibers and have not ever had this happen of fine on the first shot to destroying the case on the 4th shot. also I miked the bullets and they are good. HELP

I will try to post pictures.