R25 is another great powder to try. I've had best luck with 7828 and R25 in my last 3 257Wbys. Don't worry about book OALs with this cart when you have a factory freebore, just find what works best for accuracy and still functions in the mag. In my current 257(Rock #4 10tw with std freebore) I seat just about all loads at 3.25"
