The North Atlantic Treaty Organization (NATO; // NAY-toh; French: Organisation du traité de l'Atlantique Nord (OTAN)), also called the (North) Atlantic Alliance, is an intergovernmental military alliance based on the North Atlantic Treaty which was signed on 4 April 1949. The organization constitutes a system of collective defence whereby its member states agree to mutual defense in response to an attack by any external party. NATO's headquarters are in Brussels, Belgium, one of the 28 member states across North America and Europe, the newest of which, Albania and Croatia, joined in April 2009. An additional 22 countries participate in NATO's "Partnership for Peace", with 15 other countries involved in institutionalized dialogue programs. The combined military spending of all NATO members constitutes over 70% of the world's defence spending.
7.62 mm caliber is a nominal caliber used for a number of different cartridges. Historically, this class of cartridge was commonly known as .30 caliber, the Imperial unit equivalent, and was most commonly used for indicating a class of full power military main battle rifle (MBR) cartridges. The measurement equals 0.30 inches or 3 decimal lines, written .3" and read as Three-Line.
7.62 mm refers to the internal diameter of the barrel at the lands (the raised helical ridges in rifled gun barrels). The actual bullet caliber is normally .308 in (7.82 mm), although Soviet weapons commonly use a .311 in (7.91 mm) bullet, as do older British (.303 British) and Japanese cartridges.
The .30-06 Springfield cartridge (pronounced "thirty-aught-six" or "thirty-oh-six"), 7.62×63mm in metric notation and called "30 Gov't 06" by Winchester was introduced to the United States Army in 1906 and later standardized; it remained in use until the early 1970s. The ".30" refers to the caliber of the bullet, and the "06" refers to the year the cartridge was adopted—1906. It replaced the .30-03, 6 mm Lee Navy, and .30-40 Krag cartridges. (The .30-40 Krag is also called the .30 U.S., .30 Army, or .30 Government.) The .30-06 remained the U.S. Army's primary rifle and machine gun cartridge for nearly 50 years before being replaced by the 7.62×51mm NATO (commercial .308 Winchester) and 5.56×45mm NATO, both of which remain in current U.S. and NATO service. It remains a very popular sporting round, with ammunition produced by all major manufacturers.
Many European militaries at the turn of the 20th century were in the process of adopting service rounds loaded with pointed spitzer bullets: France in 1898, Germany in 1905, Russia in 1908, and Britain in 1910, so when it was introduced in 1903, the .30-03 service round loaded with a 220-grain (14 g) round-nose bullet and achieving a muzzle velocity of 2,300 ft/s (700 m/s) was quickly falling behind the ongoing technical evolution.
The .22 Long Rifle rimfire (5.6×15R – metric designation) cartridge is a long established variety of ammunition, and in terms of units sold is still by far the most common in the world today. The cartridge is often referred to simply as .22 LR ("twenty-two-//-//") and various rifles, pistols, revolvers, and even some smoothbore shotguns have been manufactured in this caliber. The cartridge originated from the Flobert BB Cap of 1845 through the .22 Smith & Wesson cartridge of 1857, and was developed by the American firearms manufacturer J. Stevens Arms & Tool Company in 1887 by combining the casing of the .22 Long with the 40-grain (2.6 g) bullet of the .22 Extra Long. For many decades, it has been a very popular cartridge around the world. It is one of the few cartridges that are accepted by a large variety of rifles, as well as pistols. The .22 Long Rifle and related cartridges (.22 Short, .22 Long and .22 Extra Long) use a heeled bullet, which means that the bullet is the same diameter as the case, and has a narrower "heel" portion that fits in the case.
Low cost, minimal recoil, and relatively low noise make .22 LR an ideal cartridge for recreational shooting, initial firearms training, small-game hunting and pest control. Used by Boy Scouts for the rifle shooting merit badge, .22 LR is popular among novice shooters and experts alike. The rimfire round is commonly packaged in boxes of 50 or 100 rounds, and is often sold by the brick, a carton containing either 10 boxes of 50 rounds or loose cartridges totaling 500 rounds, or the case containing 10 bricks totaling 5,000 rounds.
The .308 Winchester (pronounced: "three-oh-eight") is a rimless bottlenecked rifle cartridge and is the commercial cartridge from which the 7.62×51mm NATO round was derived. The .308 Winchester was introduced in 1952, two years prior to the NATO adoption of the 7.62×51mm NATO T65. Winchester (a subsidiary of Olin Corporation) branded the cartridge and introduced it to the commercial hunting market as the .308 Winchester. Winchester's Model 70 and Model 88 rifles were subsequently chambered for the new cartridge. Since then, the .308 Winchester has become the most popular short-action, big-game hunting cartridge worldwide. It is also commonly used for civilian target shooting, military sniping, and police sharpshooting. The relatively short case makes the .308 Winchester especially well adapted for short action rifles. When loaded with a bullet that expands, tumbles, or fragments in tissue, this cartridge is capable of high terminal performance.
Although very similar to the military 7.62×51mm NATO specifications, the .308 cartridge is not identical and there are special considerations that may apply when mixing these cartridges with 7.62×51mm NATO, and .308 Winchester chambered arms. Their interchange is, however, considered safe by the Sporting Arms and Ammunition Manufacturers Institute (SAAMI).
The 5.56×45mm NATO (official NATO nomenclature 5.56 NATO) is a rifle cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge. If the bullet impacts at high enough velocity and yaws in tissue, fragmentation creates a rapid transfer of energy which can result in dramatic wounding effects.
The .218 Bee is a .22 caliber centerfire rifle cartridge designed for varmint hunting by Winchester in 1938. The cartridge was originally chambered in lever-action rifles, which may have ultimately led to its lack of popularity. The cartridge is named for the bore diameter of the barrel in which the cartridge is chambered rather than the usual practice in the United States of having the cartridge's nomenclature reflect in some way the bullet diameter.
The .218 Bee cartridge was designed by Winchester for use in their lever-action rifles. Winchester designed the cartridge by necking down the .25-20 Winchester cartridge to accept a .224 diameter bullet. As the .25-20 had been based on the .32-20 Winchester, the .32-20 Winchester can be considered to be the parent cartridge of the .218 Bee. The cartridge was introduced as a commercial cartridge by Winchester in 1939 in their Model 65 lever action rifle, which was also chambered for the .25-20 and .32-20 Winchester cartridges. However, while the .25-20 and the .32-20 Model 65 rifles had 22 inch (560 mm) barrels, the rifles chambered for the Bee sported 24 inch (610 mm) barrels.
The 7.62×51mm NATO (official NATO nomenclature 7.62 NATO) is a rifle cartridge developed in the 1950s as a standard for small arms among NATO countries. It should not be confused with the similarly named Russian 7.62×54mmR cartridge; a slightly more powerful round.
It was introduced in U.S. service in the M14 rifle and M60 machine gun in the late 1950s. The M14 was superseded in U.S. service as the infantry adopted the 5.56×45mm NATO M16. However, the M14 and many other firearms that use the 7.62×51 round remain in service, especially in the case of sniper rifles, machine guns, and as the service weapon chosen by special operations forces. The cartridge is used both by infantry and on mounted and crew-served weapons mounted to vehicles, aircraft and ships.