I remember an article in Shooting Times where Rick Jamison (if I spelled his name correctly) shot his rifle and then re-chambered it to the next cartridge.
It showed that the velocity gain was modest from the 30-06 to the 30-06AI and then the 30Gibbs, When loaded to the same pressure!

I'm no expert, I just read the magazine several times as it had an article on 22-250 1-8 twist.

"Camping places fix themselves in your mind as if you had spent long periods of your life in them.
You will remember a curve of your wagon track in the grass of the plain like the features of a friend."
Isak Dinesen