Question: What rifle is the basis for the the magazine-fed, gas-operated semi-automatic rifle designed to be manufactured with the extensive use of aluminum alloys and synthetic materials?

full_context: Document 1: AR-15 (disambiguation): AR-15 most commonly refers to the Colt AR-15, a line of semi-automatic rifles manufactured by Colt, based on the United States military M16 rifle.
Document 2: Marlin Model 60: The Marlin Model 60, also known as the Marlin Glenfield Model 60, is a semi-automatic rifle that fires the .22 LR rimfire cartridge. Produced by Remington Arms in Mayfield, Kentucky formerly by Marlin Firearms Company of North Haven, Connecticut, it has been in continuous production since 1960 and the company says it is the most popular rifle of its kind in the world. Major features include a micro-groove barrel, a cross-bolt safety, hardwood stock with Monte Carlo comb, and brass inner magazine tube. The Marlin Model 795 is a very similar rifle and based on the Marlin Model 60, changed only to accept a detachable box magazine.
Document 3: Bushmaster Firearms International: Bushmaster Firearms International, LLC, based in Madison, North Carolina, United States, is a manufacturer and distributor of firearms. The company's product line revolves around semi-automatic pistol and rifle variants of the M4 / AR-15 design.
Document 4: AR-57: The AR-57, also known as the AR Five-seven, is an upper receiver for the AR-15/M16 rifle lower receiver, firing 5.7×28mm rounds from standard FN P90 magazines. It was designed by AR57 LLC and is currently produced by AR57 of Kent, Washington, USA. The AR-57 PDW Upper is a new design on AR-15/M16 rifles, blending the AR-15/M16 lower with a lightweight, monolithic upper receiver system chambered in FN 5.7×28mm. This model is also sold as a complete rifle, supplied with two 50-round P90 magazines. The magazines mount horizontally on top of the front handguard, with brass ejecting through the magazine well. Hollow AR-15 magazines can be used to catch spent casings.
Document 5: Kalashnikov rifle: A Kalashnikov rifle is any one of a series of automatic rifles based on the original design of Mikhail Kalashnikov. They are officially known in Russian as "Avtomat Kalashnikova" ("Kalashnikov's Automatic Gun"; Russian: Автома́т Кала́шникова ), but are widely known as Kalashnikovs, AKs, or in Russian slang, as a "Kalash". They were originally manufactured in the Soviet Union, primarily by Izhmash, but these rifles and their variants are now manufactured in many other countries.
Document 6: Automatic rifle: An automatic rifle is a type of self-loading rifle that is capable of fully automatic fire. Automatic rifles are distinguished from semi-automatic rifles in their ability to fire more than one shot in succession once the trigger is pulled. Many automatic rifles are select-fire weapons which are capable of firing in fully automatic, semi-automatic or burst-fire modes. Most automatic rifles are further subcategorized as battle rifles or assault rifles.
Document 7: Steyr Scout: The Steyr Scout is a modern scoped bolt-action rifle manufactured by Steyr Mannlicher and chambered primarily for 7.62 NATO (.308 Winchester), although other chamberings are offered commercially. It is intended to fill the role of a versatile, lightweight all-around rifle as specified in Jeff Cooper's scout rifle concept. Apart from the barrel and action, it is made primarily of polymers and is designed to be accurate to at least 300–400 meters. The Steyr Scout is also available in 5.56 NATO (.223 Remington), .243 Winchester, .376 Steyr and 7mm-08 Remington.
Document 8: Colt AR-15: The Colt AR-15 is a lightweight, 5.56×45mm, magazine-fed, gas-operated semi-automatic rifle. It was designed to be manufactured with the extensive use of aluminum alloys and synthetic materials.
Document 9: Knight's Armament Company SR-47: The SR-47 is a modern rifle based on the AR-15 family of rifles created by Knight's Armament Company for USSOCOM. Unlike the majority of ArmaLite-type guns, the SR-47 is essentially an AR-15 that fires the Soviet 7.62×39mm round from AK-47 magazines, which explains the "47" in the gun's name. The rifle was created after soldiers on long missions in Operation Enduring Freedom complained of running out of 5.56×45mm NATO ammunition for their M4 carbines but having plenty of captured AK-47 magazines. The SR-47 is basically an M4 that will accept standard AK-47 magazines rather than NATO STANAG M16/M4 mags, along with other minor modifications common to KAC's designs.
Document 10: CETME Model L: The Model L is a Spanish 5.56×45mm NATO assault rifle developed in the late 1970s at the state-owned small arms research and development establishment CETME ("Centro de Estudios Técnicos de Materiales Especiales") located in Madrid. The rifle retains many of the proven design elements the institute had used previously in its CETME Model 58 battle rifles.
Document 11: AK-101: The AK-101 is an assault rifle of the Kalashnikov series. The AK-101 is designed for the world export market, using 5.56×45mm NATO cartridges, which is the standard of most NATO armies. The AK-101 is marketed at those looking for a weapon that combines the logistical compatibility and familiarity of the 5.56×45mm NATO round with the reliability of a Kalashnikov. It is designed with modern and composite materials, including plastics that reduce weight and improve accuracy. Many of the improvements found in the AK-101 are also present in the AK-103 and the rest of the AK-100 series of rifles.
Document 12: Akdal MKA 1919: The Akdal MKA 1919 is a gas operated, semi-automatic shotgun that resembles the M16 rifle and mimics the layout and placement of some of the controls. It was created by Turkish company Akdal Arms. The MKA 1919 uses a conventional gas-operated action which is located around the support tube that runs below the barrel. The return spring is also located around the same support tube which is concealed by an enlarged polymer handguard. The MKA 1919 barrel can be quickly removed from upper receiver. To charge the rifle, the charging handle on the receiver must be pulled. The upper receiver is manufactured from an aluminum alloy while the lower receiver, along with pistol grip and shoulder stock, is manufactured as one piece from impact-resistant polymer. Akdal MKA 1919 semi-automatic rifle has a 5-round detachable box magazine. It has a bolt release identical in location and function to the one on the M16. Manual safety also duplicates M16-style being located on the left side of the receiver above the pistol grip. Standard sights include a front post installed on the M16-style removable base and a detachable M16A2-style carrying handle with built-in diopter sight. On the upper receiver, an integral Picatinny rail exists which will accept detachable carrying handle or optional red-dot or other optical sight attachments.
Document 13: Bushmaster M17S: The Bushmaster M17S is a semi-automatic bullpup rifle that was manufactured by Bushmaster Firearms International from 1992 until 2005.
Document 14: STG-556: The STG-556 is a Steyr AUG A1 a clone manufactured by Microtech Small Arms Research (MSAR). It was introduced at the 2007 SHOT Show. The STG-556's working system features a bolt release as seen on the M16 rifle; otherwise, the STG-556 retains the features similar to the Steyr AUG, such as having the quick-change barrel option and the ability to change which side the weapon ejects from by changing the bolt out for a right or left side bolt respectively. There is some parts interchangeability but the rifle is not a true clone. The STG-556 ships standard with right side ejector. The STG-556 is unable to use M16-style magazines or STANAG NATO standard magazines; they use versions of a proprietary MSAR magazine resembling the Steyr mags. The current production XM-17 E4 use STANAG magazines. The STG-556 is a short-stoke gas piston. The STG-556 rifle can be converted from either having a telescopic sight or a MIL-STD-1913 rail. It is available in civilian (semi-automatic only) and military/law enforcement (select-fire) variants.
Document 15: Browning BAR: The Browning BAR is a gas-operated, semi-automatic rifle produced by the Browning Arms Company in Belgium. The rifle loads from a box magazine detachable from a hinged floor plate. This rifle should not be confused with the M1918 military rifle, which is a completely different design, sharing no parts, though also referred to as the BAR. Browning introduced a redesigned BAR in 1966.
ground_truth: United States military M16 rifle