Thanks to everyone who has contributed.
Starting to look at small grain extruded as an option. Hodgdon Extreme powders in particular for their temp stability.
Also Tac. My local range is a Ramshot dealer. I had thought Tac was only for extra heavy bullets. But looking at the burn rate charts, it is faster than Varget, BL-C(2), W748, CFE-223, and Leverevolution...and close to Benchmark, H335, 2230, and H4895. Also, Sierra lists it as the top hunting load for the 63 SMP.
http://accurateshooter.net/Downloads/sierra223ar.pdf
