475guy- The 9.3X64 has more case capacity than the 9.3X62. I didn't run the numbers, but the base of the 62 is .476 and that of the 64 is .507. Looks like the 62 will run out of steam at 2400fps while the 64 will do 2700fps both with 286 grs bullets. I actually saw 2950 with a 250 gr nosler out of mine. Scared me to death, and I reduced the load quickly. My experience with the 9.3X64 was extremely good. By the way, I see your in Isleton.My ranch is up in Mendocino. Are you coming to the .50BMG shoot in Reno in April?-Rob