I was trying out some new reloads today in one of my Swiss K-31's and noticed the brass appeared to be separating after only one reload. The load wasn't hot and 5 shot groups were running from 1" to 2" @ 100yds. The round on the left has a Hornady 168 gr A-Max with an O.A.L. of 2.915 and the case was cut to length at 2.180. If you look closely you can see a line around the bottom of the case where it is starting to separate. You can also see from the piece of brass cut in half that there is a deep groove on the inside of the case. In the rounds that started to separate I had resized the brass with a Redding die and used 44.5grs and 45grs of Varget. I also shot 10 rounds that were resized on a RCBS die and used Prvi 168gr. HPBT's with 44.5grs. of Varget. There were no signs of separation in the cases that were resized with the RCBS die. It appears that the angle of the neck is not as steep on the brass sized with the RCBS dies and the brass sized by the Redding die seems to be pushed back 35 thousandths of an inch more than the RCBS die. This is the second time I've run into this problem shooting the Swiss rifles. I really don't believe the problem is caused by the gun but by something I am doing in prepping the brass. I've been told that bad headspace in a gun can cause this but I think there must be another explanation. Any suggestions? Thanks in advance!
Chuck
Chuck