Glad to hear that you fixed the issue. That said, Remington primers seem to have soft cups compared to CCI, and Federal.
I’ve tested their primers again recently and they’re usually very flat, and look like they were almost going to go through the cup. Those were BR 7 1/2 SRP. CCI BR and Federals would always hide the fact that it was a near max load.
25.3 VarGet behind a 73 gr. Berger BT in Lapua brass in a Remington mil-spec rifle. So much so that after I tested those REM 7 1/2’s and CCI -400 vs the Benchrest and FGMM that I lowered the charge down to 24.2.
I’ve had bad luck with Remington primers over my lifetime with FTF, and for that reason never really wanted to use them. But your results may be different.
The cup material and thickness has been the issue for me.
Years ago I experienced this problem. It was with military brass reformed to .243 Winchester. I'm sure my problem was due to lack of knowledge on my part at the time. In those days I thought brass was brass and didn't understand the differences in case capacity, neck thickness, etc. After two shots I didn't try anymore. The remainder of what I had loaded still sits on a shelf in my loading room, as a reminder of what can happen.
You have a nice, tight group at 41.5 grains. Is it reproducible? Either of the other groups will do for hunting out to three or four hundred yards. Did you check velocities?
DrMike I was just doing a charge weight test. I will test them again and check the velocities. I have to seat the bullet deeper cause it won't eject a live round.
There was a stretch of Winchester LR primers prone to piercing , suggest they be avoided.
With regard to your issue I have adopted a policy of using factory ammo only in certain rifles Not that factory ammo cannot be defective on occasions, but if that happens I won't be kicking my own ass for the pitted bolt face or chipped firing pin ! You have a gorgeous Finnwolf. I love that model (I have 3 of them). I don't shoot reloads in them.Replacing a damaged firing pin on a Finnwolf would be a major challenge.
Made it back to the range todat 43gns of varget averaged 2660. And produced this group its consistent. Very happy with it. Hope to bloody it in October when i can use it for 3 days while the weather is nice.