25 wssm question

[GaryD]

I have a new winchester model 70 stealth II rifle 25 wssm shooting factory loaded winchester ammo. The problem I am having with it is the cases are splitting half on the neck up to half way on the shoulder. I have shot a total of 15 rounds with 3 cases splitting. 2 with 95 grain bullets and one with 115 grain bullets. I have measured the fired brass with unfired brass and compared those measurements with a reloading manual and did not find anything to make me think the the brass has swelled beyond what would be normal. But I did find the neck seames dirtier than what i normally see with bolt actions, it looked what I see from an AR spent round.
Being not as knowledgable as most people on here, does anyone have an idea what is causing this?

Gary

 

[ar15topgun]

Are these nickel plated cases? If so that is the problem. Switch over to plain brass cases and that should solve your problem. Nickel plated cases are not reloader friendly and are hard on dies.

 

[effendude]

He stated he is shooting factory ammo.

Is it possible you have a dirty chamber or a scar or burr on the chamber preventing good headspace sealing? The scar or burr could also be cutting the brass. Two different bullet weights means two different lots/types of ammo so it sounds like the rifle. If you can't find anything, have a good gunsmith look at it.
Scott

 

[GaryD]

Thanks, I also think there is something wrong with the chamber. Another thing I noticed with the fired brass was the primer is much flatter and head stamp lettering seams shallower than the unfired ammo. I also compaired to a fired case from my 7mm rem mag and the primer was also much flatter. From what i have read in some reloading books and on the forum I think it may be excessive pressure?

Although I do not have anyway to measure run out, the neck on the fired cased appears to be slightly bent. Not sure what that means, I cannot think of a way a chamber could be cut with the neck being out of alignment.

I will try and get it to a gunsmith to get it checked out.

thanks

Gary