AR - 10 The AR - 10 is an American 7 . 62 mm battle rifle developed by Eugene Stoner in the late 1950s at ArmaLite , 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 lighter than other infantry rifles of the day . Over its production life , the original AR - 10 was built in relatively small numbers , with fewer than 10 , 000 rifles assembled . In 1957 , the basic AR - 10 design was rescaled and substantially modified by ArmaLite to accommodate the . 223 Remington cartridge , and given the designation AR - 15 . ArmaLite licensed the AR - 10 and AR - 15 designs to Colt Firearms . The AR - 15 would eventually become the M16 rifle . 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 , a talented small arms inventor , whom 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 was in the midst of testing several rifles to replace the obsolete M1 Garand since the Model 45A and M1946 rifle . Springfield Armory ' 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 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 and 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 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 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 , 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 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 an 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 , 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 Cummings ' 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 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 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 , Burma , Italy , Cuba , Sudan and 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 , the Netherlands , Finland , and South Africa also purchased small numbers of the AR - 10 for test purposes , and Cuba ' s Batista government ordered 100 " Transitional " model rifles in 1958 . The Cuban order was delivered to Havana , but in December 1958 Fidel Castro ' 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 , and Che Guevara 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 . 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 - 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 and Mozambique . In U . S . Army tests at Aberdeen Proving Ground 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 , the AR - 10 was much appreciated by members of the French Foreign Legion . As one police instructor in the Congo 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 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 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 , Australia , and New Zealand . 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 ( 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 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 . 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 , . 22 - caliber selective - fire rifle accurate to 500 yards . In response , ArmaLite engineers Gene Stoner , Jim Sullivan , and Bob Fremont used the basic AR - 10 design to produce the AR - 15 in . 223 Remington , which was completed as a firing prototype in 1958 . 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 Firearms , 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 share of 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 , gas - operated rifle that uses the direct impingement gas principle with a rotary bolt locking mechanism . The rifle has a conventional layout ; it features an in - line stock , an aluminum alloy receiver and a reinforced fiberglass 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 - era StG44 . The bolt locking mechanism is similar to the M1941 Johnson rifle ( itself an adaptation of the Browning - designed Remington Model 8 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 . Legacy AR - 10 production . 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 . Notably , the AR - 10B was not designed using the original AR - 10 drawings from either ArmaLite or Artillerie Inrichtingen , but instead was based on the Colt AR - 15A2 , with parts scaled up or redesigned as needed to fire the 7 . 62x51mm NATO ( . 308 Winchester ) 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 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 an 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 . Current users include the Ontario Provincial Police Tactics and Rescue Unit . While ArmaLite Inc . holds a US trademark on the name " AR - 10 " , other rifle manufacturers currently produce 7 . 62x51mm auto - loading rifles that are based generally on the AR - 10 design : the DPMS LR - 308 , KAC SR - 25 , Rock River Arms LAR - 8 , American Spirit Arms ASA . 308 , Fulton Armory Titan , LWRC ' s R . E . P . R . , LaRue Tactical ' s OBR , RND Manufacturing ' s " The Edge " , the German Oberland Arms OA - 10 , the Lewis Machine and Tool LM308MWS , Bushmaster MOE 16 . 308 and Smith & Wesson M & P10 .