I'm loading this 275 grain cast: It says COL should be 1.70". Well, when seated at that length, I can't get a good roll crimp because its not on the cannelure. Why would they give that COL then? So, I seated four where it crimped on the cannelure and shot them at just above the minimum charge (2400). Very accurate, no pressure signs. So I'm working my way up on the charge looking for pressure signs. I just don't know why they have that long of a COL? Another question..I have some older Federal brass that has this ring close to the case mouth. It looked fine until I ran the expander die through a few and it looks as though the top part of the case mouth is could almost split at that ring and come off, what a calamity that would be. Any comments on the brass? I'm afraid that gas check may catch it on exit.