BsChoy, sure, all laws of physics apply... but your shoulder doesn't gauge pressure spike, timing (fractions of seconds), and velocity.
Burn rate of powder is critical in the Garand. A SAAMI max pressure spike after the bullet has passed the gas port and you end up with a bent op-rod.
A slower powder used in a load that gives the same velocity as a faster burning powder(charges adjusted accordingly) will give your shoulder less of a snap during recoil, but increases force on the op-rod due to the max pressure spike occurring when the bullet is at or past the gas port.
That's why a chronograph is imperative to hand loading for semi-autos, and it's even more imperative to stick between documented starting and max loads with documented powders.
SteveinPA, he's using 4064, not 4895 like shown in your documented targets.
IMR data on .30-06
here. Please note that 47.0grs is STARTING LOAD for the 4064. STARTING LOAD for 4895 is 49.0grs.
From the NRA Publication "The M1 Rifle" here are the .mil equivalent loads for commercial cases (download by 1.5gr to start with mil cases):
147/150 gr Bullet
IMR3031 = 48gr
IMR4895 = 49gr
IMR4064 = 50gr
Win 748 Ball 48.0 grs.
Acc AA2460 49.0 grs.
Acc AA2520 51.0 grs.
Acc 2495BR 50.5 grs.
Hod H-4895 49.0 grs.
Hod BL-C2 49.0 grs.
Hod H-335 49.0 grs.
Herc Re-12 48.0 grs.
165/168 gr Bullet
IMR4895 = 47gr
IMR4064 = 48gr
173/175 gr Bullet
IMR4895 = 46gr
IMR4064 = 47gr
180 gr Bullet
IMR4895 = 43gr