I believe the answer is headspace, but I haven't seen this as prevalent as this before in a bolt gun.
Gun is a rem 700 sps 204 ruger, new WW brass I FL sized in Redding dies, deburred flash hole uniformly, chamfered inside and out, a batch of 10 reloads of 39 SBK and 25.5 H335 powder. 5 of the 10 had flush or below primers, and the other had .001 to .004" primer height above flush, using the depth rod on vernier micrometers. Dragging a precision ruler across case base you can feel the primers are well above the base and also see it. The edges of the primers are rounded, so a hot load isn't the problem, imho.
I had a similar issue many years ago with a contender in 7 tcu, and found the case fit in the chamber deeper than was correct. My fix was to bump the neck up to 30 cal, slowly resize down until the action barely closed, fixing the problem. Some cases in the contender were so deep they soft hit the primer and didn't go off......
I suspect my chamber may be deep and I need to bump all the brass.... but not sure this is the right fix..
Thanks for any suggestions.
BTW, this also has cratering like most newer remingtons from research, but this is not a measurment of the crater.
Allen
Check that with a case gauge before you do much more. I just had a batch of new Remington .35 Whelen brass that was all short on head space By about .030 so I'm not sold on a deep chamber yet.
I expanded the necks to .375 and ran them through the Whelen die again and the cases were perfect after fire forming. Ya just never know. Bear
