AR-10
Encyclopedia
The AR-10 is an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 7.62 mm battle rifle
Battle rifle
A battle rifle is a military service rifle that fires a full power rifle cartridge, such as 7.62x51mm NATO. While the designation of battle rifle is usually given to post-World War II select fire infantry rifles such as the H&K G3, the FN FAL or the M14, this term can also apply to older military...

 developed by Eugene Stoner
Eugene Stoner
Eugene Morrison Stoner is the man most associated with the design of the AR-15, which was adopted by the US military as the M16...

 in the late 1950s at ArmaLite
ArmaLite
ArmaLite is the name of a small arms engineering facility founded in the early 1950s, and once associated with the Fairchild Engine and Airplane Corporation. ArmaLite was formally incorporated as a subdivision of Fairchild on October 1, 1954...

, then a division of the Fairchild Aircraft Corporation. When first introduced in 1956, the AR-10 used an innovative straight-line barrel/stock design with phenolic composite and forged alloy parts resulting in a small arm significantly easier to control in automatic fire and over 1 lb (0.45359237 kg) lighter than other infantry rifles of the day. The unique features of the AR-10 would eventually be developed into the U.S. Army's
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

 M16
M16 rifle
The M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...

. Over its production life, the original AR-10 was built in relatively small numbers, with fewer than 10,000 rifles assembled.

History and development

ArmaLite began as a small engineering concern founded by George Sullivan, the patent counsel for Lockheed Corporation, and funded by Fairchild Engine and Airplane Corporation. On October 1, 1954, the company was incorporated as the ArmaLite Corporation, becoming a subdivision of Fairchild. With its limited capital and tiny machine shop, ArmaLite was never intended to be an arms manufacturer. The company focused on producing small arms concepts and designs to be sold or licensed to other manufacturers. After leasing a small machine shop at 6567 Santa Monica Boulevard in Hollywood, California, Sullivan hired several employees and began work on a prototype for a lightweight survival rifle for use by downed aircrew.

While testing the prototype of ArmaLite's survival rifle design at a local shooting range, Sullivan met Eugene Stoner
Eugene Stoner
Eugene Morrison Stoner is the man most associated with the design of the AR-15, which was adopted by the US military as the M16...

, a talented small arms inventor, who Sullivan immediately hired to be ArmaLite's chief design engineer. At the time, ArmaLite Inc. was a very small organization (as late as 1956 it had only nine employees, including Stoner). With Stoner as chief design engineer, ArmaLite quickly released a number of interesting rifle concepts.
The first prototypes of the 7.62 mm AR-10 emerged during 1955 and early 1956. At the time the United States Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

 was in the midst of testing several rifles to replace the obsolescent M1 Garand since the Model 45A
Model 45A
The Model 45A was a battle rifle / light machine gun developed by the United States Army in the Philippines in 1945. The weapon existed in prototype or mockup form, but never entered production...

 and M1946 rifle
M1946 Sieg automatic rifle
The M1946 Sieg automatic rifle was a bullpup battle rifle / light machine gun designed by James E. Sieg of the US Coast Guard. The weapon, introduced to the public in 1946, was chambered in the .30-06 round, fed from 20 round magazines and is capable of firing around 650-700RPM in full automatic...

. Springfield Armory
Springfield Armory
The Springfield Armory, located in the City of Springfield, Massachusetts - from 1777 until its closing in 1968 - was the primary center for the manufacture of U.S. military firearms. After its controversial closing during the Vietnam War, the Springfield Armory was declared Western Massachusetts'...

's T44E4 and heavier T44E5 were essentially updated versions of the Garand chambered for the new 7.62 mm round, while Fabrique Nationale submitted their FAL
FN FAL
The Fusil Automatique Léger or FAL is a self-loading, selective fire battle rifle produced by the Belgian armaments manufacturer Fabrique Nationale de Herstal . During the Cold War it was adopted by many North Atlantic Treaty Organization countries, with the notable exception of the United States...

 as the T48.

ArmaLite's AR-10 entered the competition late, hurriedly submitting two hand-built 'production' AR-10 rifles based on the fourth prototype in the fall of 1956 to the United States Army's Springfield Armory for testing. The AR-10 prototypes (four in all) featured a straight-line stock design, rugged elevated sights, an oversized aluminum flash suppressor/recoil compensator, and an adjustable gas system. In the fourth and final prototype, the upper and lower receiver were hinged with the now-familiar hinge and takedown pins, the charging handle did not reciprocate, and was not attached to the bolt carrier. For a 7.62mm NATO rifle, the AR-10 prototype was incredibly lightweight at only 6.85 lbs. empty. Initial comments by Springfield Armory test staff were favorable, and some testers commented that the AR-10 was the best lightweight automatic rifle ever tested by the Armory.

Unfortunately for ArmaLite, the rifle's aluminum/steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 composite barrel (an untried prototype design specified for the tests by ArmaLite's president, George Sullivan, over Stoner's vehement objections) burst in a torture test conducted by Springfield Armory in early 1957. ArmaLite quickly replaced it with a conventional steel barrel, but the damage had been done. The final Springfield Armory report advised against adoption of the rifle, stating that "it would take five years or more to take it through tests to adoption". While ArmaLite objected, it was clear that the AR-10, a brand-new rifle still in the prototype stage, was at a disadvantage compared to competing designs with longer development cycles, and by 1957, U.S. Army infantry forces urgently required a modern, magazine-fed infantry rifle to replace the M1. In the end the Army chose the conventional T44, which entered production as the M14 rifle
M14 rifle
The M14 rifle, formally the United States Rifle, 7.62 mm, M14, is an American selective fire automatic rifle firing 7.62x51mm NATO  ammunition. It was the standard issue U.S. rifle from 1959 to 1970. The M14 was used for U.S...

 in 1957. That same year, ArmaLite completed about 50 production AR-10 rifles at its workshop for use as demonstrator models for its sales agents, including Samuel Cummings
Samuel Cummings
Samuel Cummings, was an American small arms dealer. He founded the International Armament Corporation in 1953, a company which came to dominate the free world market in private arms sales.-Biography:Cummings was born in Philadelphia and became interested in weapons after acquiring a Maxim Gun...

, a famous international arms dealer. Attempts to rush completion of these fifty rifles resulted in a few units that were assembled with improperly machined barrel extensions, a defect that went unnoticed at the time. These production rifles built at ArmaLite's workshop in Hollywood would later become known as the Hollywood model.

On July 4, 1957, Fairchild ArmaLite sold a five-year manufacturing license for the AR-10 to the Dutch
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 arms manufacturer, Artillerie Inrichtingen (A.I.). With its large factory and production facilities, A.I. could produce the ArmaLite rifle in the large quantities that Fairchild expected would be forthcoming.

In 1957 Cummings secured a order of 7,500 AR-10 rifles from Nicaragua, with an initial delivery of 1,000 rifles to be delivered before January 1958. The order was contingent on a successful completion of a 7,500-round endurance test. With the AR-10 in short supply, Cummings left his personal demonstrator rifle with Nicaragua's chief military commander, General Anastasio Somoza
Anastasio Somoza Debayle
Anastasio Somoza Debayle was a Nicaraguan leader and officially the 73rd and 76th President of Nicaragua from 1 May 1967 to 1 May 1972 and from 1 December 1974 to 17 July 1979. As head of the National Guard, he was de facto ruler of the country from 1967 to 1979...

, who would personally conduct the endurance test trial. While General Somoza was firing this rifle for the trial, the bolt lug over the ejector sheared off and flew past Somoza's head. The general angrily returned Cumming's AR-10 and canceled the entire Nicaraguan order. The remaining Hollywood rifles were inspected and refitted as necessary with new parts to prevent reoccurrence of the bolt lug failure, but the Nicaraguan order was lost for good.

A.I. officials meanwhile discovered a number of manufacturing and production issues in the Hollywood version of the AR-10, all of which had to be resolved before large-scale production could commence. In addition to designing and building tooling for the rifle, the design had to be converted to metric dimensions and subcontractors had to be found to supply materials or manufacture component parts. ArmaLite also continued to send A.I. product improvement requests, including an adjustable regulator, a repositioned gas tube, and a new three-prong flash suppressor. Accessories such as flash hiders, bayonet mounts, sling swivels, and sight graduations had to be designed.

Firearms historians have separated AR-10 production under the AI license into at least three basic identifiable versions, along with various sporting, carbine
Carbine
A carbine , from French carabine, is a longarm similar to but shorter than a rifle or musket. Many carbines are shortened versions of full rifles, firing the same ammunition at a lower velocity due to a shorter barrel length....

 and other experimental designs and calibers. The three main variants have been termed the Sudanese model, the Transitional, and the Portuguese model AR-10. A.I. built all of these rifles, beginning with the Sudanese model AR-10. The Sudanese version derives its name from its sale to the Government of Sudan, which purchased approximately 2,500 AR-10 rifles in 1958. The Sudanese was equipped with a very lightweight, fluted steel barrel fitted with a trim, prong-style flash suppressor, a bayonet lug, lightweight fiberglass furniture, and sight graduations in Arabic. The Sudanese weighed only 3.3 kg (7.3 lb) with an empty magazine. The price, including cleaning kit and four magazines, was US $225 per rifle. All AR-10s, whether produced by ArmaLite or by A.I., used the same Stoner-designed 20-round lightweight aluminum 'waffle' magazine with pressed-in, corrugated sides, intended to be discarded in combat once emptied.
AR-10 production was limited, though Guatemala
Military of Guatemala
The Military of Guatemala consists of National Army of Guatemala , the Guatemalan Navy and the Guatemalan Air Force ....

, Burma
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....

, Italy
Military of Italy
The Italian armed forces are the military of Italy, they are under the command of the Italian Supreme Council of Defence, presided over by the President of the Italian Republic. The total number of active military personnel is 293,202...

, Cuba
Military of Cuba
The Cuban Revolutionary Armed Forces consist of ground forces, naval forces, air and air defence forces, and other paramilitary bodies including the Territorial Troops Militia , Revolutionary Armed Forces , and Youth Labor Army .The armed forces has long been the...

, Sudan
Military of Sudan
The Sudanese Armed Forces numbers, according to 2007 IISS estimates, 104,800 members supported by 17,500 paramilitary personnel.It comprises Land Forces, a Navy, an Air Force, and the Popular Defence Force. It has also formed Joint Integrated Units with its rebel enemies the Sudan People's...

 and Portugal
Portuguese Army
The Portuguese Army is the ground branch of the Portuguese Armed Forces which, in co-operation with other branches of the Portuguese military, is charged with the defence of Portugal...

all purchased AR-10 rifles for limited issue to their military forces. Sudanese AR-10s were employed in frequent clashes with guerrilla forces and conflicts with neighboring countries, and a few captured rifles eventually turned up in unofficial service with various African and colonial armies, police, and guerrilla forces. The AR-10 remained in service with Sudanese Special Forces until 1985. In 1958, a special 7.62x39mm caliber variant of the Sudanese AR-10 was produced in very small numbers for evaluation by Finland and Germany. That same year, a 16" barreled AR-10 was developed in response to a request by KLM Airlines for a carbine that could be issued to their crew for transpolar flights as part of an Arctic survival kit, and approximately 30 carbines were eventually produced. A number of Transitional AR-10s were also fitted with a folding bipod designed to lie flat under the forearm. The Italian Navy acquired the AR-10 for its COMSUBIN underwater commando teams. Germany, Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

, the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, Finland, and South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 also purchased small numbers of the AR-10 for test purposes, and Cuba's Batista
Fulgencio Batista
Fulgencio Batista y Zaldívar was the United States-aligned Cuban President, dictator and military leader who served as the leader of Cuba from 1933 to 1944 and from 1952 to 1959, before being overthrown as a result of the Cuban Revolution....

 government ordered 100 "Transitional" model rifles in 1958. The Cuban order was delivered to Havana, but in December 1958 Fidel Castro
Fidel Castro
Fidel Alejandro Castro Ruz is a Cuban revolutionary and politician, having held the position of Prime Minister of Cuba from 1959 to 1976, and then President from 1976 to 2008. He also served as the First Secretary of the Communist Party of Cuba from the party's foundation in 1961 until 2011...

's forces took control of the country, including the warehouse containing the AR-10 shipment. In 1959, in response to a letter from ArmaLite's sales agent Sam Cummings, Castro invited Cummings to Havana to discuss payment for the AR-10 rifles. Fidel, his brother Raúl
Raúl Castro
Raúl Modesto Castro Ruz is a Cuban politician and revolutionary who has been President of the Council of State of Cuba and the President of the Council of Ministers of Cuba since 2008; he previously exercised presidential powers in an acting capacity from 2006 to 2008...

, and Che Guevara
Che Guevara
Ernesto "Che" Guevara , commonly known as el Che or simply Che, was an Argentine Marxist revolutionary, physician, author, intellectual, guerrilla leader, diplomat and military theorist...

 test-fired the AR-10 outside Havana. Impressed by the weapon's firepower, Castro paid Cummings for all 100 rifles. However, rapidly worsening relations with the United States eliminated any chance of future AR-10 sales to Cuba, and Castro transferred the ex-Batista AR-10s to a group of communist revolutionaries from the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...

. In June 1959, the rebels, led by Cuban officers, invaded the Dominican Republic in a combined seaborne and airborne landing. Betrayed by local residents, the seaborne rebel forces were surprised at the water's edge; those dropping via parachute were hunted down in the following days by the Dominican army. Captured AR-10 rifles from the Batista shipment were found on the bodies of guerrillas killed in firefights with government forces.

The final Artillerie Inrichtingen design is known as the Portuguese model AR-10. This final version incorporated all that had been learned to date about the AR-10, including infantry service rifle and field test reports. In addition to a heavier barrel with chrome-lined chamber, optional bipod, and the removable plastic/metal handguards of the Transitional model, the Portuguese variant had wider bolt lugs, a stronger extractor, a new simplified three-position gas regulator, and a cocking handle featuring a forward bolt assist. It is believed that approximately 4-5,000 Portuguese variants were produced; nearly all of them were sold to the Portuguese National Defense Ministry by the Brussels
Brussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...

-based arms dealer SIDEM International in 1960. The AR-10 was officially adopted by Portuguese Hunter paratroop (Caçadores páraquedista) battalions, and the rifle saw considerable combat service in Portugal's counter-insurgency campaigns in Angola
Angola
Angola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city...

 and Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...

. In U.S. Army tests at Aberdeen Proving Ground
Aberdeen Proving Ground
Aberdeen Proving Ground is a United States Army facility located near Aberdeen, Maryland, . Part of the facility is a census-designated place , which had a population of 3,116 at the 2000 census.- History :...

 in November 1960, and later in Portuguese service, the AR-10 gained a reputation for accuracy (some rifles would group into 25 mm (1 inch) at 100 meters with service ammunition). Portuguese paratroopers found the AR-10 to be not only accurate but reliable in combat, despite rugged service conditions in African jungle and savannah. A few Portuguese and Sudanese model AR-10s found their way by various means to nearby African countries; in Chad
Chad
Chad , officially known as the Republic of Chad, is a landlocked country in Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic to the south, Cameroon and Nigeria to the southwest, and Niger to the west...

, the AR-10 was much appreciated by members of the French Foreign Legion
French Foreign Legion
The French Foreign Legion is a unique military service wing of the French Army established in 1831. The foreign legion was exclusively created for foreign nationals willing to serve in the French Armed Forces...

. As one police instructor in the Congo
Democratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...

 stated, "It was a good combat weapon that never failed me; a bit too long (but not as bad as the FAL or M-14) for house-to-house work or really heavy brush, but great for 400-800 meters, in the flats - and really nice on the body, after wandering around 12-14 hours looking for bad guys."

Some Portuguese-model AR-10s were fitted with A.I.-modified upper receivers in order to mount 3x or 3.6x telescopic sights. These rifles were used by marksmen accompanying small patrols to eliminate individual enemies at extended ranges in open country. Other AR-10s were used by the paratroopers in a secondary role to launch rifle grenade
Rifle grenade
A rifle grenade is a grenade that uses a rifle-based launcher to permit a longer effective range than would be possible if the grenade was thrown by hand...

s. The AR-10's built-in gas cutoff design enabled it to fire Energa rifle grenades without adjustment of the gas system, and the self-loading action would even eject the spent blank shells and load the next one, allowing several grenades to be quickly fired. The added recoil took its toll on rifle stocks, and some Portuguese rifles were retrofitted with all-metal buttstocks to better withstand the strain caused by firing the heavy grenades. Plans to order additional quantities of the AR-10 rifle were stymied after the Netherlands embargoed further shipments of the rifle to Portugal. Paratroopers deploying to Africa in later years were subsequently issued a collapsible stock version of the German Heckler & Koch G3
Heckler & Koch G3
The G3 is a 7.62mm battle rifle developed in the 1950s by the German armament manufacturer Heckler & Koch GmbH in collaboration with the Spanish state-owned design and development agency CETME ....

 rifle. Nevertheless, the AR-10 continued in service with a few Portuguese airborne units, and was in use as late as 1975 in the Portuguese Timor (East Timor) decolonization emergency.

Fairchild-ArmaLite was dissatisfied with the delays in setting up the tooling and production at A.I. for the AR-10, and made it clear that they would not be renewing A.I.'s license to produce the rifle. By 1960, hampered by Dutch export restrictions and discouraged by the lack of arms sales to major national purchasers, Artillerie Inrichtingen decided to exit the small arms production business altogether, and ceased all production of the AR-10 under its license from Fairchild-ArmaLite. By that time, less than 10,000 AR-10s had been produced, mostly military select-fire rifles, with a few semi-automatic only rifles produced for civilian use. All A.I. AR-10 parts inventories, tooling, and prototypes were either sold or scrapped; the barrel tooling was sold to Israel sometime in the early 1960s. All AR-10 production records, design drawings, manuals, literature, and other publications then in inventory were discarded.

In later years, some ex-military Sudanese and Portuguese model AR-10s were sold to civilian markets in the U.S., Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. Nearly all of the rifles imported to the latter three countries had their full-automatic fire selector disabled. Subsequently, as many as 2,500 Australian AR-10 rifles may have been confiscated and destroyed as a result of more restrictive firearms legislation passed in 1997.

Most of the AR-10 ex-military rifles shipped to the USA were in the form of parts kits, having been previously dismantled, though a few were legally imported as National Firearms Act
National Firearms Act
The National Firearms Act , 73rd Congress, Sess. 2, ch. 757, , enacted on June 26, 1934, currently codified as amended as , is an Act of Congress that, in general, imposes a statutory excise tax on the manufacture and transfer of certain firearms and mandates the registration of those firearms. The...

 (NFA) weapons. Large numbers of AR-10 7.62 mm magazines were imported as well. Many of these kit rifles were combined with various semi-auto receivers made by civilian manufacturers in order to permit legal ownership. During the early 1980s, the Joliet, Illinois
Joliet, Illinois
Joliet is a city in Will and Kendall Counties in the U.S. state of Illinois, located southwest of Chicago. It is the county seat of Will County. As of the 2010 census, the city was the fourth-most populated in Illinois, with a population of 147,433. It continues to be Illinois' fastest growing...

 based Paragon Sales and Services manufactured new semi-automatic lower receivers while using imported upper AR-10 receivers originally manufactured by Artillerie-Inrichtingen in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

.

In 1957, in an effort to increase profits from the ArmaLite venture, Fairchild decided to compete in the U.S. Army's CONARC requirement for a new six-pound, high-velocity, small-caliber selective-fire rifle accurate to 500 yards. In response, the following year ArmaLite engineers Gene Stoner, Jim Sullivan, and Bob Fremont developed the 5.56 mm
5.56x45mm NATO
5.56×45mm 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...

 AR-15
AR-15
The AR-15 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials....

 from the first or 'Hollywood' version of the AR-10. Fairchild-Armalite continued its efforts to sell both the AR-10 and AR-15 to various military forces around the world. However, the AR-10 rifle marketed by ArmaLite after 1958 was not the product-improved AR-10 developed by Artillerie Inrichtingen, but rather a design scaled-up from AR-15 plans and specifications, the AR-10A. None of the improvements incorporated by Artillerie Inrichtingen over three years of production were used in the new AR-10A. Although the AR-10A did not benefit from the modifications undertaken by the Dutch licensee, it had some differences from the AR-15 (besides caliber and part dimensions), including a different bolt, trigger, and cocking handle design, along with a magazine canted forward at a five-degree angle. While interest in the AR-15 was considerable, the AR-10A failed to attract any orders from domestic or foreign military customers. In 1959, ArmaLite sold its rights to the AR-10/AR-15 to Colt
Colt's Manufacturing Company
Colt's Manufacturing Company is a United States firearms manufacturer, whose first predecessor corporation was founded in 1836 by Sam Colt. Colt is best known for the engineering, production, and marketing of firearms over the later half of the 19th and the 20th century...

, who successfully marketed the AR-15 to the U.S. military. Eugene Stoner left the company in 1961. Disappointed with ArmaLite's marketing efforts, Fairchild sold its ArmaLite in 1962 to George Sullivan with the financial backing of Capital Southwest Corporation of Dallas, Texas.

Design details

The AR-10 is a lightweight, air-cooled, magazine-fed, select-fire
Selective fire
A selective fire firearm has at least one semi–automatic and one automatic mode, which is activated by means of a selector which varies depending on the weapon's design. Some selective fire weapons utilize burst fire mechanisms to limit the maximum or total number of shots fired automatically in...

 gas-operated
Gas-operated reloading
Gas-operation is a system of operation used to provide energy to operate autoloading firearms. In gas-operation, a portion of high pressure gas from the cartridge being fired is used to power a mechanism to extract the spent case and chamber a new cartridge. Energy from the gas is harnessed...

 rifle that uses the direct impingement
Direct impingement
Direct impingement is a type of gas operation for a firearm that directs gas from a fired cartridge directly to the bolt carrier or slide assembly to cycle the action.- Evaluation :...

 gas principle with a rotary bolt
Rotating bolt
Rotating bolt is a method of locking originally developed by Ferdinand Ritter von Mannlicher and found in his Steyr-Mannlicher M1895 straight-pull bolt-action rifle designed for and issued to the Austro-Hungarian Army...

 locking mechanism. The rifle has a conventional layout; it features an in-line stock, an aluminum alloy receiver and a reinforced fiberglass
Fiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...

 pistol grip, handguard, and buttstock. While mostly an original design, the AR-10 built upon previously proven concepts. From the FAL it took the hinged receiver system allowing the rifle to be opened for cleaning much like a break-action shotgun. The ejection port cover is similar to that found on the German World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

-era StG44. The bolt locking mechanism is similar to the M1941 Johnson rifle (itself an adaptation of the Browning
John Browning
John Moses Browning , born in Ogden, Utah, was an American firearms designer who developed many varieties of military and civilian firearms, cartridges, and gun mechanisms, many of which are still in use around the world...

-designed Remington Model 8
Remington Model 8
The Remington Model 8 is a centerfire, recoil-operated, semi-automatic rifle designed by John Browning and produced by Remington Arms beginning in 1906.John Browning was granted on October 16, 1900 for the rifle, which he then sold to Remington...

 bolt). From the German FG42 and M1941 Johnson machine gun came the idea of straight-line stocks to reduce muzzle climb in fully automatic fire. The AR-10's method of rotary bolt locking, straight-line recoil, and gas operation enhanced its inherent accuracy.

The gas system, bolt carrier, and bolt-locking design were novel for the time. Most gas-operated rifles divert combustion gases from a port in the barrel to a piston and cylinder arrangement adjacent to the port. In Stoner's design, the gas travels from a port near the middle of the barrel through a steel tube back into the receiver. The gas enters a chamber formed between the rear of the bolt and the inside of the bolt carrier. Once the bolt carrier moves to the rear a small distance, excess gas is vented through holes in its side. This use of the bolt and bolt carrier for the separate actions of a piston and gas cylinder simplified construction and saved weight. Movement of the bolt carrier was in-line with the bore, greatly improving inherent accuracy, as well as keeping the rifle on target as the gun fired. Since the straight-line stock placed the shooter's eye well above the barrel the rifle's sights were mounted high, with the rear sight contained in a carrying handle that also protected the cocking/charging lever.

The receiver is made from forged and machined aluminum to reduce weight. The bolt locks into an extension on the barrel instead of the receiver allowing for a lightweight receiver while not compromising the strength of the bolt locking mechanism. On a few prototype guns, an all-aluminum ("Sullaloy") barrel was fitted at the insistence of George Sullivan – ArmaLite's president – though after the 1957 Springfield Armory tests, all production AR-10s were fitted with standard steel barrels. The stock is made from a phenolic composite reinforced fiberglass with a core of rigid plastic foam. The handguards and pistol grip are also fiberglass. Fairchild was an aircraft manufacturer, and the use of plastics, titanium, and aluminum were common in the aircraft industry at the time, though not generally used in firearms.

Several experimental prototypes of a belt-fed variant of the AR-10 were developed by ArmaLite and A.I. engineers, informally designated the AR-10 LMG. In one version, the belt was fed by a feed-chute connected to a 250-round ammo box carried on the user's back. All of the belt-fed prototypes experienced numerous issues with feed malfunctions and parts breakages, and these problems were never wholly solved during the weapon's development stage, which ended with the termination of A.I.'s production contract. As a result, no AR-10 LMG variants were ever sold.

ArmaLite AR-10B rifle series

In 1995, former Army Ordnance officer Mark Westrom, owner of Eagle Arms, purchased the ArmaLite brand and the company became ArmaLite Inc. Shortly thereafter, ArmaLite Inc. introduced a completely new rifle, collectively known as the AR-10B rifle series. The new ArmaLite AR-10B was not based on the original ArmaLite AR-10, but rather the AR-15A2
AR-15 variants
This article is a review of many variations of the AR-15 family of weapons. Weapons patterned on the original ArmaLite AR-15 have been produced by numerous manufacturers and have been used by nations around the world, some of which created their own variations. The tables here are split in a...

, with parts scaled up or redesigned as needed to fire the 7.62x51mm NATO (.308 Win) cartridge. The AR-10B prototype was composed of individual sub-components tested on a special lower receiver made of two slabs of aluminum fitted to a Knights Armament Company SR-25
SR-25
The SR-25 is a semi-automatic sniper rifle designed by Eugene Stoner and manufactured by Knight's Armament Company. The SR-25 uses a rotating bolt and a direct impingement gas system. It is loosely based on Stoner's AR-10, rebuilt in its original 7.62×51mm NATO caliber...

 upper receiver assembly, and prototyped using computer analysis. The full prototype AR-10B was the first rifle off the production line. Since 1995, the new ArmaLite company has also incorporated various other design and engineering improvements to the AR-10, including a newly designed steel magazine derived from the model used on the U.S. M14 rifle. The current ArmaLite AR-10 is offered in several versions including a A2 and A4 rifle or carbine with collapsible stock, a target model (AR-10T), a 'retro' AR-10B with Sudanese AR-10-style handguard and cocking lever (limited production) and one version chambered in 300 Remington SAUM
.300 Remington SA Ultra Mag
.300 Remington Short Action Ultra Magnum is a .30 caliber short magnum cartridge that was put on the market shortly after Winchester released its 300 WSM round in 2001.-Performance:...

. Current users include the Ontario Provincial Police
Ontario Provincial Police
The Ontario Provincial Police is the Provincial Police service for the province of Ontario, Canada.-Overview:The OPP is the the largest deployed police force in Ontario, and the second largest in Canada. The service is responsible for providing policing services throughout the province in areas...

 Tactics and Rescue Unit.

While ArmaLite Inc. holds a US trademark on the name "AR-10", other rifle manufactures currently produce .308 semi-auto rifles that are based on the AR-15/AR-10 design: the DPMS LR-308, KAC SR-25
SR-25
The SR-25 is a semi-automatic sniper rifle designed by Eugene Stoner and manufactured by Knight's Armament Company. The SR-25 uses a rotating bolt and a direct impingement gas system. It is loosely based on Stoner's AR-10, rebuilt in its original 7.62×51mm NATO caliber...

, Rock River Arms
Rock River Arms
Rock River Arms, Incorporated is a manufacturing company based in Colona, Illinois that manufacturers parts and accessories for AR-15/M16 type rifles, as well as complete firearms.-Law Enforcement Use:...

 LAR-8, American Spirit Arms
American Spirit Arms
American Spirit Arms is a manufacturer of firearms and firearm components. Their products include complete rifles, assemblies, parts and accessories. The company's products are built in the US, at their facility in Scottsdale, AZ....

ASA .308, Fulton Armory Titan, LWRC's R.E.P.R., LaRue Tactical's OBR, RND Manufacturing's "The Edge" and the German Oberland Arms OA-10.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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