I hadn't yet gotten to PT&G, so I appreciate the pointer. I was losing faith with nothing from Manson, Clymer, 4D, etc.
I don't intend to push this too hard in the velocity department. I know McWhorters 6.5's do not carry the traditional Weatherby freebore. I shoot a lot of 257 Weatherby and get more than acceptable (to me) accuracy with the factory chamber. I can see reasons both ways.