What I dont understand is the 308 M1s use 1/12 twist and the 30-06 M1s use 1/10. The 1/12 is more accurate with the 150 grain projectiles maybe they didnt under twist rates as well back then , the M1 ball with its longer bullet profile worked well with the 1/10 but they stopped using it in the 30s. I have also never seen an M1 barrel chambered in 30-06 with 1/12 always 1/10 Im sure there were some made? im assumingI wouldn't call it a controversy...just tactics changed and the M1906/M2 round was primarily intended for training while the AP was the primary combat ammo.
The M1 was very accurate but also expensive to make.