Franklin Armory M4-SBR-M Semi-Automatic Rifle 7.62x51mm 14.5" Barrel (1)-20Rd Magazine Magpul MBUS Sights CTR Folding Stock Black Finish

The 7.62X51mm NATO cartridge was adopted by the U.S. in the M14 rifle in 1957. NATO adopted it in the same year, but in other platforms. The 7.62X51mm is essentially a shortened 30-06 case, allowing a more compact action and more compact ammunition at very minor cost in performance. A side benefit--which might not have been anticipated--is improved accuracy because of the greater efficiency of the shorter case. Although 7.62X51mm has been largely supplanted by the 5.56X45mm NATO cartridge in service rifles, it is still widely used by militaries around the world and remains a primary cartridge for light and medium machineguns. Due to its exceptional accuracy it is also a very common cartridge for military sniping at ranges to a bit beyond 1000 yards. The civilian version, the 308 Winchester, was introduced in 1952 while the 7.62X51MM was still in the experimental stages. — Craig Boddington