Don,
I bought 2000 of these earlier this year, and then did some research where they are only recommended for lower pressure uses like 22 hornet and the like. Some internet wisdom and pictures out there of pitted bolt faces in AR from them not holding up to the high pressure loadings.
They've been working great for 38spl and 357mag for me for my plinking rounds with Titegroup, WSF, and 2400. They don't seem quite hot enough for LilGun, leaves some unburnt powder in my 6" revolver.
Hope that helps,
Terry