I started with the 61 grain load from my buddies book that showed right at max for Retumbo. Again even with this load I was getting cratering right from the get go and this kind of torqued me off a bit as it is a light load.
Is that a typo? Did you mean min rather than max?
Have you measured the amount of protrusion of the firing pin from the bolt face?
Is the shape of the firing pin wide with rounded edges? Or, perfectly half round?
Does there appear to be slop in the hole around the firing pin?
I have a Steyr 223 that pierced a couple of primers the last time I used it with a new box of Superformance that I'd never tried before. It could be bad primers. But, I plan to inspect/measure the firing pin. Before I shoot it again.