HorseSoldier
Member
If we had deployed the Garand in .276, the rifles, BARs and machine guns would have fired different rounds. The ammo makers would have had to split their production between two different rounds. Supply would have been a nightmare.
During WW2, we had tons of M1 carbines in service along with 30-06 rifles and MGs (plus a good number of 45 ACP submachineguns in the mix, too) and things seem to have worked out okay.
My recollection is that at least part of the motive for the M1 carbine was that the Garand in 30-06 was heavier than the 276 version, and so not suitable for guys who needed a PDW. I'm not sure I buy that 100% -- surely an M1 carbine would still be a handier weapon than a somewhat lighter Garand, but the softer shooting 276 round would have worked better in a cut down carbine version shooting the same cartridge than 30-06 would.
Anyway, upshot being that I don't think a 276 caliber service rifle and 30-06 machineguns would have overly complicated things above and beyond the real world complications we had with logistics.