As far as primers, There are certainly some with harder cups than others. In large rifle primers, the toughest I have found are the Wolf primers and BR2s are second.
As stated. The small rifle primers have less surface area and are less susceptible to deformation. Not sure how this translates into real world results but if someone is suggesting that it makes it safe to push 75,000 PSI because the primers hold, I would disagree with them.
