My Sniper School Instructor had served in WWII, Korea, Vietnam he used a Delta Mdl Garand 30-06 and when the Army switched to the M-14 .308 he said he lost about 200 yards with the caliber switch.
Great read Mike. I know that when I researched the M1 Garand to purchase one, that finding one with the rare "Gas Trap" was slim to none, and would cost a pretty penny if found. The one I purchased was enough 's as it was.