7.62 × 51 mm NATO

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NATO's 7.62 × 51 mm rifle cartridge, otherwise known as .308 Winchester (though they do not have identical specifications), was introduced in the 1950s as a standard firearm cartridge among NATO countries — though it has also become popular among civilians. There are many types, such as tracers and blanks, as well as many makes of the round.

It was introduced to service with a variety of firearms, primarily service rifles and machine guns. It is used in the M14 rifle and M60 machine gun in US service in the late 1950s. The cartridge was earlier selected for NATO standardization. Fabrique Nationale's FN FAL became the most popular 7.62 rifle in Europe and served into the early 1980s. The M14 was superceded in US service due to a change to a round for infantry with the M16, the M14 and many other firearms that use the round remain in service. The round is used by infantry as well as on vehicles, aircraft, and from ships. It use used in the GE minigun as well.

1 Overview
2 Development
3 Firearms using the NATO round
4 See also
5 External links

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Overview

The round itself offers similar ballistic performance in most firearms to the round it replaced in U.S. service, the .30-06. While the cartridge itself is shorter, the actual bullet and loadings are about the same (muzzle velocities on the order of 860 m/s (2800 fps) for both). The advantage of the smaller case is that less brass is used and firearms that use the round can be smaller (for a similar example, compare .45 GAP and .45 ACP). The downside is that the smaller case of the 7.62 × 51 mm is exactly tailored to the military loading, and it is less suitable for heavier bullets and slower burning, lower density powders (see internal ballistics).

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Development

The development work that would eventually develop into the 7.62 × 51 started just after World War I, when it became clear that the long cartridge of the US standard .30-06 round made it difficult to use in semi- and fully-automatic weapons (the .30-06 was in turn derived from an earlier .30-03 cartridge, and had more case capacity than was needed). A "shorter" round would allow the firing mechanism to be made much smaller, and improve the feeding, both of which would allow for higher rates of fire. At the time one of the most promising designs was the .276 Pedersen, but in 1932 it was rejected with an Army recommendation that only rounds of .30 inch (7.62 mm) would meet requirements.

Thus when the war appeared to be looming again only a few years later, the .30-06 was the only round available. Nevertheless the US Army did use it to great effect in the excellent M1 Garand, which provided US troops with considerably higher firepower than most of their bolt action armed opponents. The Garand performed so well that the US saw little need to replace it until almost a decade later, and the .30-06 remained in service until well after the Korean War.

During the 1940s and early 1950s several experiments were carried out in order to improve upon the Garand. One of the most common complaints was the difficulty in reloading the weapon using its "en bloc clips", and many experimental designs modified the weapon with a detachable box magazine. One of these, Springfield Armory's T20, was a fully-automatic version. The US Army finally found this design to be worthy enough to consider replacing the Garand, and decided it was also time to look at improved ammunition once again.

The test program continued for several years, including not only the original .30-06, but a modified .300 Savage (then known as the T65) as well. In the end, the T65 design demonstrated power roughly equal to the original .30-06, while being somewhat shorter and much more reliable in feeding. The T44, an adaptation of the T20 to fire the new round, was the almost-uncontested winner of the competition.

When the US announced its intentions to introduce the T65, the British were incensed. They had considerable evidence to demonstrate that their own .303 British could not be controllably fired in a shoulder fired automatic rifle, and the somewhat more powerful T65 would be even harder to control. They had spent considerable time and effort developing an intermediate-power round, the .280, to solve these problems. The US countered with their pre-WWII requirements that stated that only a .30 caliber design would do. After considerable fighting between the two armed forces, the argument was settled in unlikely fashion when the Canadian Army announced they would be happy to use the .280, but only if the US did as well -- a tacit agreement to use the T65, as it was clear the US would not use the .280. The T65 was chosen as the NATO standard in 1954.

The T44 was adopted as the M14 in 1957. FN FAL's started delivery in Britain and Canada around the same time, with the West German army adopting a modified version of the Spanish CETME rifle, as the G3. However it was not long before those involved realized the British had been right all along, the .308 could not reliably be fired in full-auto due to recoil. M14's were later delivered with the full-auto selection locked out, and adaptations to the FAL to allow it included the addition of a bipod and heavier barrel.

While all of this was going on, the US's Project SALVO had concluded that a burst of four rounds into a 20 inch circle would cause twice the number of casualties as a full-auto burst by one of these "battle rifles" -- regardless of the size of the round. They suggested using a much smaller .22 caliber cartridge with two bullets per round (a "duplex load"), while other researchers investigated the promising flechette rounds which were even lighter but offered better penetration than even the .30-06. These studies were kept secret in case the British found out about them and used that as evidence in favour of their smaller rounds.

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When the M14 arrived in Vietnam with US troops, it was found to be ungainly. The rifle's length and weight were poorly suited for jungle warefare. Troops were less able to compete with the manuverable AK47. Also, the larger rounds were heavy and did not allow for much ammunition to be carried.

Fighting between the big-round and small-round groups reached a peak in the early 1960s, when test after test showed the "puny" .223 Remington round fired from the AR-15 allowed an 8 soldier unit to vastly outgun an 11 soldier unit armed with M14's, and beat the typical NVA unit armed with AK47's. In 1964, the US Army started replacing their M14's with the M16, setting off another firestorm of complaints from the British.

Regardless of being poorly suited for jungle warfare. 7.62 × 51 mm rifles stayed in military service around the world due to several factors. 7.62 NATO has proved much more effective than 5.56 at long ranges. It has become prolific as a sniping round. For instance, the M14 is still used in the United States military as a sniper rifle. Some rifles were much more successful than the M14. Shorter, more manuverable, 7.62 rifles like the Heckler & Koch G3 stayed in service due to their accuracy, range, power, and reliability.

The 7.62 nevertheless proved itself an excellent mid-sized round, accomplishing everything the designers had hoped in terms of full-auto reliability. It remained the main squad machine gun round for almost all NATO forces well into the 1990s, even being used in adapted versions of older .30-06 machine guns such as the Browning M1919A4 from the WWII era. These too have been replaced to some extent by .223 weapons, notably the widespread Minimi, but they remain the primary armament on most flexible mountings such as helicopters, jeeps, and tanks.

Winchester saw the market for a civilian model of the T65 round in 1952, and it remains a popular game round to this day as the .308 Winchester. The cartridge is very popular with American sportsmen both for long-range target shooting and hunting big game up to the size of elk or moose.

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