Dirtfarmer,
I take my post about having no problems with 527 firing pins back--partly.
Noted earlier that small-rifle primers vary far more than LR primers. Many are made specifically for low pressures, which were normal in all cartridges taking SR primers for many years, such as the .25-20. Primers designed for such rounds (which included the .22 Hornet and .218 Bee) not only don't burn very hot, but often have very soft cups, probably to accomodate lower-strength firing pin or hammer springs. One such primer even has copper cups, instead of brass.
The .222 Remington operated at a little higher pressures and SR primers started getting both hotter and somewhat tougher, but after the .223/5.56 and some other high-pressure rounds on the same basic case came along in the 1960's, primer companies started making much hotter and tougher SR primers.
As noted earlier, I habitually test several different primers in small cartridges, but not just to see how they affect accuracy and velocity, but to see how they handle pressures. I did this in my CZ 527 .17 Hornet and three "softer" primers all cratered badly, with firing pin holes almost to the point of piercing. But two showed no trace of either, the CCI 450 and Remington 7-1/2, both designed for higher-pressure rounds. They also happen to be the most accurate primers I've found in my three rifles chambered for Hornet-case rounds.
