The 7.62x51 mm cartridge is a NATO standard, and a very common ammunition around the world - in the US it is also known as the .308 Winchester.

The 7.62 was born from the development on the FN FAL rifle by the weapons manufacturer Fabrique National in Belgium. As a model was used the 7.92x33 mm Kurtz used by the Germans in their Sturmgewehr 44 during World War II. But post-war influences called for a heavier round, and the 7.62x51 mm was created. The 7.62 could easily be manufactured by a simple conversion of the common .30 caliber ammunition mills, and the round was adopted as a NATO standard caliber.

The 7.62 suffers from a few problems as a military round compared to a smaller caliber, such as the 7.92x33 mm. It is heavy and large - reducing the soldiers ammunition loadout, and reducing magazine capacity. It has a heavy recoil and thus reduces the rate of fire. Automatic because of the physical impossibility to control the weapon. Single-shot series because the recoil will force the shooter to re-align his rifle significantly between shots.
Military means soon called for a smaller - easily manageable round, and found its answer in the 5.56x45 mm.

The 7.62 has not completely been phased out from military service. Whereas the 5.56 mm round replaced the 7.62 as the assault rifle ammunition of choice, the 7.62 is still the preferred caliber for larger weapons platforms such as machine guns, anti aircraft guns, vehicle-mounted weapons and of course sniper ammunition.

As a sniper ammunition, the 7.62 is THE round. The 7.62 has outstanding ballistics and consistent behavior, which is outperformed by only a few ammunition types. One reason for this is the historical fact that the 7.62's cousin, the .30 caliber round has long been a great performer, and thus more research of this caliber class has been spent than on any round available.

The US Army claims an 800 meter effective range, whereas the US Marine Corps preaches a 1000 meter effective range. 800 meters is generally considered an effective range for consistant hits. Since beyond that range the .308 loses its otherwise flat trajectory and behaves irregularly.

The 7.62 is not quite as popular as the 5.56 in law enforcement use, since the 7.62 tends to over-penetrate its target and cause damage to non-targets.

For a sportsman, the 7.62 is a great game round! Almost anything is huntable with this caliber, and combined with it's amazing accuracy it is the most common hunting round in the world. Although it is not really recommended for plinking since it has a rather nasty recoil and will sore up your shoulder rather quickly.