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 ( " 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 Model A , B and C series of battle rifle s . The weapon was successfully trialled between 1981 – 1982 and approved for serial production in 1984 at the Empresa Nacional Santa Bárbara factory ( currently Santa Bárbara Sistemas , integrated into General Dynamics European Land Combat Systems division ) . The Model L replaced the 7 . 62mm CETME Model C in service with the Spanish Army and the first rifles were delivered in 1987 , by which time orders for approximately 60 , 000 had been placed . It has now been largely replaced in Spanish service with a license - built variant of the Heckler & Koch G36E . Design details . Operating mechanism . The Model L is a selective fire , roller - delayed blowback firearm . The weapon features a semi - rigid two - piece bolt mechanism that consists of a bolt head and a supporting angular locking piece . During the " unlocking " sequence , the two cylindrical rollers contained in the bolt head are cammed inward against inclined flanks of the barrel extension and act upon the locking piece and bolt carrier , propelling it rearward at a velocity greater than that of the bolt , which remains closed until the fired bullet has left the barrel and pressures inside the bore have been reduced to a safe level before withdrawing together with the bolt carrier . Features . The bolt also has a cartridge casing extractor , while the ejector is located inside the trigger housing ( the extractor is lifted by the recoiling bolt carrier , actuated with every shot ) . The weapon is hammer - fired and has a fire control lever , which is also the manual safety . The safety and fire selector lever is located on the left side of the receiver , directly above the pistol grip , and has three settings : " S " ( Spanish : Seguro ) — weapon safe ( trigger is disabled mechanically ) , " T " ( Spanish : Tiro a tiro ) — semi - automatic fire and " R " ( Spanish : Ráfaga ) — fully automatic fire ( initial production rifles also had a burst selector option , which was abandoned ) . The Model L fires from a closed bolt position and uses the NATO - standard 5 . 56x45mm cartridge loaded with the 62 - grain SS109 projectile . INI ( Instituto Nacional de Industria , a state factory ) made ammunition was dirtier and gave much more chamber pressure than standard NATO ammunition , and was one of the sources of reliability problems ( hard primers were in part responsible , too ) . At NATO joint exercises , foreign units tended to be warned not to use Spanish ammo if their rifles were gas operated [ sources needed ] . The rifle ' s barrel features 6 right - hand grooves and a rifling twist rate of 1 in 178 mm ( 1 : 7 in ) ; it is fitted with an open - type 3 - prong flash suppressor , and later a " birdcage " style one , both designed to launch rifle grenade s . The weapon will also mount a knife - type bayonet . The Model L ' s fixed stock , pistol grip and handguard are made of a high - strength lightweight plastic . The rifle strips down into the following components for regular maintenance and cleaning : the receiver , stock , pistol grip and trigger group , handguard , bolt , bolt carrier and recoil mechanism . Handguards in the first several series were " square " in section ( see LC picture ) , covering from magazine well to front sight . This gave some problems with heat retention , so it was changed to a round " half length " handguard made of thicker plastic , over the full length stamped steel support piece . Almost all military rifles changed to the new handguard , but Guardia Civil rifles retained the squared version . Feeding . The rifle feeds from standard NATO magazines that adhere to STANAG specifications ( interchangeable with magazines from the M16 rifle ) and have a 30 - round capacity , but it can also use short 12 - round box magazines , usually only used for parades ( early rifles and carbines were also adapted to use special 20 and 30 - round magazines that were of an entirely different design ) . Issued magazines were steel , but thick walls only gave several problems , like misfeedings , stuck magazines ( some could not even be inserted in the rifles ) , and the like . Although they were supposed to be expendable ( a cost of 25 pesetas in 1995 ) , it was forbidden to discard them , and many soldiers were punished for losing a magazine . Spanish soldiers tried to keep magazines known to work well for themselves , or get other STANAG magazines from surplus stores or friends abroad . It was a common sight in NATO joint exercises to see Spanish soldiers searching the zone where US troops discarded their empty mags . Many reliability problems were solved by using these " non - - issued " magazines . Sights . The CETME Model L is equipped with adjustable iron sight s consisting of a forward post ( corrected mechanically for elevation ) in two versions " thick " and " thin " ( no official designation ) . Thin post was better for precission shooting , but it could easily bend if hit . Since it was well protected this wasn ' t much of a problem , and it was preferred over the thicker version . A flip - up rear sight with two settings for firing at distances of 200 and 400 m ( early models had a rotating drum rear sight that provided 100 , 200 , 300 and 400 m sighting range apertures ) . The Model LV ( " Visor " ) is a marksman variant equipped with a fixed STANAG mount over the rear sight base ; the optic generally used in this role is the British SUSAT sight in some units , the standard being a nationally produced 4 power ENOSA scope . An starlight scope was also available . Another model with a rotating drum rear sight used by the Infanteria de Marina was also called LV , leading to some confusion , even in training manual and logistics . The standard rear sight base has an horizontal pin forward , and a circular shallow cavity behind were a detachable scope base could be mounted , but almost never used since not many of these bases were made for general use . Accessories . Standard equipment supplied with the rifle includes a cleaning kit , sling , bayonet , lightweight bipod , blank - firing adaptor , rifle grenade launcher guide and magazine loader tool . Variants . A variant of the Model L is the Model LC carbine that has a short barrel and a collapsible metal shoulder stock , making it particularly suitable for officers , special forces and riot police . These features also allow a high degree of movement in closed spaces or moving vehicles . This carbine version however cannot be used with a bayonet or rifle grenades .