| United States|
| 1923–1932 (experimental)|
The .276 Pedersen (7×51mm) round was an experimental 7 mm cartridge developed for the U.S. Army and used in the Pedersen rifle and early versions of what would become the M1 Garand.
.276 Pedersen Wikipedia
Developed in 1923 in the United States, it was intended to replace the .30-06 Springfield in new semi-automatic rifles and machine guns. When first recommended for adoption, M1 Garand rifles were chambered for the .276 Pedersen, which held ten rounds in its unique en-bloc clips. The .276 Pedersen was a shorter, lighter and lower pressure round than the .30-06, which made the design of an autoloading rifle easier than the long, powerful .30-06. The U.S. Army Chief of Staff Gen. Douglas MacArthur rejected the .276 Pedersen Garand in 1932 after verifying that a .30-06 version was feasible.