Use CCI Small Rifle Primers to solve the problems. They are typically a harder cup.
Also, invest in a set of Redding Dies. I junked my LEE set for this very issue (inconsistent neck tension) , and have not had a pierced primer issue yet in my Savage 12LRPV.
I am loading 25.2gr H322 behind a 40gr VMax pill, and only see a slight flowing on the primers.
.204 brass should not grow at the neck. The 35 degree shoulder helps to prevent that from happening provided you load to the COL length as specified in reloading.
Even after 12 loadings, neck sized only, the brass is still within .003 of virgin brass length. I find that the best accuracy is observed AFTER the brass has been reloaded 3 times or better.
Be vigilant of cracking near the case mouth, DO NOT FL resize this brass until you are ready to toss it. I discovered this early on, that a FL resize tends to overwork the brass after it has been fire formed to your chamber, and will fail soon afterwards.
In the same token, fire a loaded round. Keep it. Take that piece and install it in your press, then pull handle and screw in the neck sizing die down to it. When the die is snug, give it another 1/16" turn, and keep it there for future sizing needs.
The theory is that once fire formed, if you can resize the neck as close as possible to YOUR firearm, and still hold a bullet, it will not work harden the brass to failure as fast as sizing back down to virgin brass size.
Some of my brass is over 25 firings old and shows no signs of deterioration. But the norm seems to be about 12 firings-18 firings and then the brass tends to show signs of developing cracks.
Hope this helps.
