Ian of Forgotten Weapons shows off the .276 Garand that almost was, the T3E2:
By 1932, the competition for the new US semiautomatic service rifle had been narrowed down to just two designs: John Pedersen’s delayed blowback toggle action and John Garand’s gas-operated action. Both rifles were chambered for Pedersen’s .276 caliber cartridge, and used 10-round en bloc clips. Twenty samples of each were made and sent out to infantry and cavalry units for field testing.
This rifle is one of those Garands — serial number 15, to be specific. The results of the trial was a preference for the Garand rifle, and the testing board got as far as writing a formal recommendation for its adoption before General MacArthur vetoed the whole .276 caliber idea for economic and logistical reasons (the US Army had a whole lot of .30-06 ammo and not a lot of spare cash). The result was ultimately a .30 caliber Garand rifle becoming the M1, but this T3E2 trials rifle in .276 sure is a sweet-handling piece of machinery!
The Army screwed up the initial release of the M16 for various logistical reasons, too.
For all the hype it gets, the Garand was obsolete when the troops went ashore at Normandy, of course the Lee-Enflield was, too. Both the Germans and the Russians were fielding better weapons to some of their troops, and both realized that assault troops needed automatic weapons, not perfected WW I trench rifles.
In the event, most American troops were equipped with M1 Carbines, which were common, if not dominant, even in infantry units. The M2 Carbine was the US’s first assault weapon.