In JOC's 1961 "Complete Book of Rifles and Shotguns", page 147, he said he never found a better .270 load than 49.5 gr of IMR-4064 with a 130 gr bullet.
He mentions IMR-4350 as the slowest IMR powder.
Perhaps this is prior to his finding H4831.
For .30-06, he recommended 4320.
