CETME Ameli
Encyclopedia
The Ameli is a 5.56mm
light machine gun
designed for the Spanish Army
(Ejército de Tierra) by the nationally owned and operated Centro de Estudios Técnicos de Materiales Especiales (CETME
) small arms research institute (founded by the Spanish
government in 1950).
Development of the weapon began in 1974 under the supervision of the Colonel José María Jiménez Alfaro (who would later become the director of CETME). The Ameli was officially unveiled in 1981 and after undergoing exhaustive military trials—adopted into service in 1982 as the standard squad-level support weapon of the Spanish Army under the designation MG82. The Ameli is manufactured at the Empresa Nacional Santa Bárbara factory (now General Dynamics Santa Bárbara Sistemas
) in Corunna
.
and externally resembles the 7.92mm
MG 42 machine gun of World War II
and its post-war variant—the West German
MG 3. However, unlike the MG 42's roller-locked short recoil operating principle (where the barrel and bolt recoil together a short distance before they unlock), the Ameli uses the delayed blowback method of operation with a fixed barrel and a pair of rollers which retard the rearward movement of the bolt. This mechanism was employed in CETME's Model A, B, C and Model L
series of rifles, and also in the Heckler & Koch G3
battle rifle
, HK33 assault rifle
and MP5
series of submachine gun
s. Similarities with the 7.62mm Model C and 5.56mm Model L rifles extend to the interchangeability of certain parts.
The heart of the operating system is the bolt
assembly, which consists of a bolt head, locking piece and two cylindrical rollers, which upon chambering a round, are displaced outwards by angled surfaces in the forward pressing locking piece and into notches in the barrel extension. The geometry of the walls in the barrel extension and the locking piece ensure that once a shot is fired, the bolt head absorbs the recoil impulse from the ignited cartridge
through the base of the empty casing and transmits this rearward pressure onto the rollers forcing them out of their sockets and inward at a mechanical disadvantage. The rollers then come into contact with inclined surfaces on the locking piece and propel it backwards at a speed that is approximately 1.5x greater than that of the bolt head, thereby increasing the bolt's inertia
and providing a delay in the blowback sequence. The relatively short initial rear displacement of the bolt head immediately after firing and the calculated delay eliminate the probability of a premature case extraction from the chamber (beyond the thick-walled base of the chamber) that would result in the spent casing bursting as the breech is opened only after the bullet has exited the barrel and gas pressures inside the bore have dropped to within safe limits.
and uses a striker firing mechanism (in which the bolt and internally channeled firing pin perform the role of a striker). The trigger mechanism permits fully automatic fire only but the rate of fire can be adjusted by using bolts of varying weight, like in the MG 3. The lighter bolts will produce the maximum rate of fire (1,200 rounds/min) while a heavier bolt results in a rate of fire of approximately 850–900 rounds/min. The weapon features a cross-bolt type safety
that disables the sear
when pressed into the "safe" position.
The machine gun is fed from an open-link disintegrating M27 ammunition belt
that can be strung loosely from the feed tray or placed inside a 100 or 200-round disposable plastic container, which is then clipped to the left side of the receiver
. This ammunition container has a transparent rear wall that allows the gunner to monitor ammunition levels visually. Belt movement is carried out by a pawl-type feeding mechanism, which was modeled on the MG 42's feed system. Spent cartridge casings are ejected downward through a chute in the receiver.
The quick-change type air-cooled barrel is equipped with a slotted flash suppressor
. The barrel has a chrome-lined
bore with 6 right-hand grooves and a 178 mm (1:7 in) rifling
twist rate that is optimized for use with heavier SS109 5.56x45mm NATO
rounds. A barrel with a 305 mm (1:12 in) twist rate designed specifically to stabilize the lightweight M193 cartridge is also available. The chamber portion of the barrel has flutes that assist in the extraction sequence; once gas pressure in the bore drops to a safe level, recycled gases fill the flutes surrounding the cartridge casing, loosening the case from the chamber walls while residual pressure in the barrel forces it back to be ejected downward and forward. A fixed carrying handle is positioned above the barrel near the chamber, and aids in barrel changes when the barrel becomes too hot; the barrel can be removed and replaced in 5 seconds.
The Ameli is fitted with a molded
polymer
stock, bipod
and iron sight
s that consist of a forward post and a rear aperture sight contained in the carry handle assembly with 300, 600, 800 and 1,000 m range settings. The weapon's design makes extensive use of sheet metal
stampings; both the receiver, barrel shroud and trigger housing are fabricated from steel
pressings
and then welded
. The quick-detach bipod has a height adjustment feature and is mounted to the perforated barrel heat shroud at the muzzle end. The light machine gun can be deployed with the bipod, on a vehicle mount or on a static tripod mount.
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...
light machine gun
Light machine gun
A light machine gun is a machine gun designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.-Characteristics:...
designed for the Spanish Army
Spanish Army
The Spanish Army is the terrestrial army of the Spanish Armed Forces responsible for land-based military operations. It is one of the oldest active armies - dating back to the 15th century.-Introduction:...
(Ejército de Tierra) by the nationally owned and operated Centro de Estudios Técnicos de Materiales Especiales (CETME
CETME
CETME is an acronym for Centro de Estudios Técnicos de Materiales Especiales , a Spanish government design and development establishment. While being involved in many projects CETME was mostly known for its small arms research and development...
) small arms research institute (founded by the Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
government in 1950).
Development of the weapon began in 1974 under the supervision of the Colonel José María Jiménez Alfaro (who would later become the director of CETME). The Ameli was officially unveiled in 1981 and after undergoing exhaustive military trials—adopted into service in 1982 as the standard squad-level support weapon of the Spanish Army under the designation MG82. The Ameli is manufactured at the Empresa Nacional Santa Bárbara factory (now General Dynamics Santa Bárbara Sistemas
General Dynamics
General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...
) in Corunna
Corunna
Corunna is the traditional English name of the city of A Coruña in Spain and the surrounding province A Coruña .Battles*Battle of Corunna, fought near Corunna in 1809*Battle of the Corunna Road, fought near Madrid in 1936–37...
.
Operating mechanism
The Ameli is an automatic weaponAutomatic firearm
An automatic firearm is a firearm that loads another round mechanically after the first round has been fired.The term can be used to refer to semi-automatic firearms, which fire one shot per single pull of the trigger , or fully automatic firearms, which will continue to load and fire ammunition...
and externally resembles the 7.92mm
7.92x57mm Mauser
The 8×57mm IS is a rimless bottlenecked rifle cartridge. The 8×57mm IS was adopted by the German Empire in 1905, and was the German service cartridge in both World Wars...
MG 42 machine gun of 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...
and its post-war variant—the West German
West Germany
West Germany is the common English, but not official, name for the Federal Republic of Germany or FRG in the period between its creation in May 1949 to German reunification on 3 October 1990....
MG 3. However, unlike the MG 42's roller-locked short recoil operating principle (where the barrel and bolt recoil together a short distance before they unlock), the Ameli uses the delayed blowback method of operation with a fixed barrel and a pair of rollers which retard the rearward movement of the bolt. This mechanism was employed in CETME's Model A, B, C and Model L
CETME Model L
The Model L is a Spanish 5.56mm assault rifle developed in the late 1970s at the state-owned small arms research and development establishment CETME located in Madrid...
series of rifles, and also in the 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 ....
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...
, HK33 assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
and MP5
Heckler & Koch MP5
The Heckler & Koch MP5 is a 9mm submachine gun of German design, developed in the 1960s by a team of engineers from the German small arms manufacturer Heckler & Koch GmbH of Oberndorf am Neckar....
series of submachine gun
Submachine gun
A submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...
s. Similarities with the 7.62mm Model C and 5.56mm Model L rifles extend to the interchangeability of certain parts.
The heart of the operating system is the bolt
Bolt (firearm)
A bolt is a mechanical part of a firearm that blocks the rear of the chamber while the propellant burns.In manually-operated firearms, such as bolt-action, lever-action, and pump-action rifles and shotguns, the bolt is held fixed by its locking lugs during firing, forcing all the expanding gas...
assembly, which consists of a bolt head, locking piece and two cylindrical rollers, which upon chambering a round, are displaced outwards by angled surfaces in the forward pressing locking piece and into notches in the barrel extension. The geometry of the walls in the barrel extension and the locking piece ensure that once a shot is fired, the bolt head absorbs the recoil impulse from the ignited cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
through the base of the empty casing and transmits this rearward pressure onto the rollers forcing them out of their sockets and inward at a mechanical disadvantage. The rollers then come into contact with inclined surfaces on the locking piece and propel it backwards at a speed that is approximately 1.5x greater than that of the bolt head, thereby increasing the bolt's inertia
Inertia
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...
and providing a delay in the blowback sequence. The relatively short initial rear displacement of the bolt head immediately after firing and the calculated delay eliminate the probability of a premature case extraction from the chamber (beyond the thick-walled base of the chamber) that would result in the spent casing bursting as the breech is opened only after the bullet has exited the barrel and gas pressures inside the bore have dropped to within safe limits.
Features
The Ameli fires from an open boltOpen bolt
A semi or full automatic firearm is said to fire from an open bolt if, when ready to fire, the bolt and working parts are held to the rear. When the trigger is pulled the bolt goes forward, feeding a round from the magazine into the chamber and firing it...
and uses a striker firing mechanism (in which the bolt and internally channeled firing pin perform the role of a striker). The trigger mechanism permits fully automatic fire only but the rate of fire can be adjusted by using bolts of varying weight, like in the MG 3. The lighter bolts will produce the maximum rate of fire (1,200 rounds/min) while a heavier bolt results in a rate of fire of approximately 850–900 rounds/min. The weapon features a cross-bolt type safety
Safety (firearms)
In firearms, a safety or safety catch is a mechanism used to help prevent the accidental discharge of a firearm, helping to ensure safer handling....
that disables the sear
Sear (firearm)
In a firearm, the sear is the part of the trigger mechanism which holds the hammer or striker back until the correct amount of pressure has been applied to the trigger; at which point the hammer or striker is released to discharge the weapon...
when pressed into the "safe" position.
The machine gun is fed from an open-link disintegrating M27 ammunition belt
Belt (firearm)
A belt or ammunition belt is a device used to retain and feed cartridges into a firearm. Belts and the associated feed systems are typically employed to feed machine guns or other automatic weapons...
that can be strung loosely from the feed tray or placed inside a 100 or 200-round disposable plastic container, which is then clipped to the left side of the receiver
Receiver (firearms)
In firearms terminology, the receiver is the part of a firearm that houses the operating parts. The receiver usually contains the bolt carrier group, trigger group, and magazine port. In most handguns, the receiver, or frame, holds the magazine well or rotary magazine as well as the trigger mechanism...
. This ammunition container has a transparent rear wall that allows the gunner to monitor ammunition levels visually. Belt movement is carried out by a pawl-type feeding mechanism, which was modeled on the MG 42's feed system. Spent cartridge casings are ejected downward through a chute in the receiver.
The quick-change type air-cooled barrel is equipped with a slotted flash suppressor
Flash suppressor
A flash suppressor, also known as a flash guard, flash eliminator, flash hider, or flash cone, is a device attached to the muzzle of a rifle or other gun that reduces the visible signature of the burning gases that exit the muzzle. This reduces the chances that the shooter will be blinded in dark...
. The barrel has a chrome-lined
Chrome plating
Chrome plating, often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal object. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness.-Process:A component to be chrome plated will...
bore with 6 right-hand grooves and a 178 mm (1:7 in) rifling
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
twist rate that is optimized for use with heavier SS109 5.56x45mm NATO
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...
rounds. A barrel with a 305 mm (1:12 in) twist rate designed specifically to stabilize the lightweight M193 cartridge is also available. The chamber portion of the barrel has flutes that assist in the extraction sequence; once gas pressure in the bore drops to a safe level, recycled gases fill the flutes surrounding the cartridge casing, loosening the case from the chamber walls while residual pressure in the barrel forces it back to be ejected downward and forward. A fixed carrying handle is positioned above the barrel near the chamber, and aids in barrel changes when the barrel becomes too hot; the barrel can be removed and replaced in 5 seconds.
The Ameli is fitted with a molded
Molding (process)
Molding or moulding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern....
polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
stock, bipod
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...
and iron sight
Iron sight
Iron sights are a system of shaped alignment markers used as a sighting device to assist in the aiming of a device such as a firearm, crossbow, or telescope, and exclude the use of optics as in telescopic sights or reflector sights...
s that consist of a forward post and a rear aperture sight contained in the carry handle assembly with 300, 600, 800 and 1,000 m range settings. The weapon's design makes extensive use of sheet metal
Sheet metal
Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material...
stampings; both the receiver, barrel shroud and trigger housing are fabricated from 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...
pressings
Stamping (metalworking)
Stamping includes a variety of sheet-metal forming manufacturing processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining. This could be a single stage operation where every stroke of the press produce the desired form on the sheet...
and then welded
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...
. The quick-detach bipod has a height adjustment feature and is mounted to the perforated barrel heat shroud at the muzzle end. The light machine gun can be deployed with the bipod, on a vehicle mount or on a static tripod mount.