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Tuesday, March 19, 2013

CETME mod.A



Army and Weapons | CETME mod.A | The state of the Spanish company CETME (Centro de Estudios Tecnicos de materiales especiales - Special Materials Technical Studies Center, now known as Empresa National Santa Barbara) was established in 1949 to develop a small arms range of the Spanish army. At the same time arms used Vorgrimler German designer Ludwig, who worked for the famous Mauser Werke in Germany before and during World War 2. Vorgrimler is the designer of the experimental German assault rifle, known as "Gerat 06" or Stg.45 (M). The rifle was not produced in quantity, but the design is presented as a basis for further development in the CETME, and more importantly, in another German company, Heckler & Koch, which obtained a license for the gun design Vorgrimler / CETME around 1957. This deal later resulted in the famous family from H & K weapons, like the G3 and HK33 assault rifles, HK21 and HK23 machine guns, MP5 submachine guns and various other small arms that reached worldwide popularity. All the weapons are built using delayed blowback operating system, designed by Vorgrimler and his men at the Mauser in 1945 and refined by CETME.
 
Initial assault rifle development at the CETME carried around between proprietary cartridge, known as 7.92x40mm CETME. This display bullet cartridges are long and slender, made of aluminum. The overall design was found adequate, but cartridge was rejected for the 7.62x51mm round with lighter bullet and a reduced powder charge. Improved rifle entered serial production in 1956 and was adopted by the Spanish army in 1957. In 1958 CETME introduced a slightly improved design, known as Modelo B or Model 58. The rifle is intended to reduce the burden of fire 7.62x51mm but also could fire the standard 7.62mm NATO, if the bolt and return spring replaced with a set of corresponding sections. In 1964, CETME introduced the Modelo C, which was also adopted by Spanish Army, Navy and Air Force. The rifle was intended to fire only standard, full-power ammunition 7.62x51mm NATO. The main improvement is the 4-position diopter sights (instead of the previous type leaves open sights), wooden handguards instead of earlier steel, bipod was made as a separate part and, most importantly, the room was fluted to improve extraction and avoid torn rims and cartridge case failures in conditions harsh environments. Modelo C rifle stopped production in 1976, and in the 1980s it has been gradually replaced by its 5.56mm derivative, CETME Modelo L assault rifle.All 7.62mm CETME rifles are built around a system of roller delayed Vorgrimlers' blowback. The system uses a two-piece bolt with two rollers. Front bolt part (bolt head) is relatively light and has a bolt face with extractor on it. It also has a hollow cavity in the rear, where an inclined forward end of the rear bolt (bolt body) is inserted. The system has two rollers, inserted from the side of the bolt head and the rest in the sloping front end of the body bolts. When the gun is fired, the pressure began to move the cartridge back against the bolt face. Roller, which extended into the recesses of the barrel extension, began to move into the into the bolt head, due to its sloping of niches.  

This movement translates into the faster rearward movement of the bolt body weight, so that, at the initial moments of shot, when pressure in the chamber is still high, bolt face moves relatively slowly. When the pressure drops to a reasonable level, rollers detach barrel extension completely and from this moment on the bolt head and the bolt body move backward at the same speed, extracting and ejecting spent case and chambering the fresh cartridge on the way back. All CETME rifle firing from a closed bolt. Hammer fired trigger mechanism, and in military versions is capable in semi-automatic mode and full automatic fire. In early models the safety / fire mode selector switch located above the trigger on the right side of the gun. Security model of C / selector switch was moved to the left side of the gun. 

The receiver is made from steel sheet stampings, and trigger housing group, which is hinged to the receiver just behind the magazine. Early models (prior to Modelo C) issued with integral folding metallic bipods and open leaf-type rear sight. The Modelo C rifles issued with wooden handguards and a separate detachable bipods. Rear sights were replaced by the 4-position diopter sights, marked for the 100-400 meter range. All rifles featuring wooden buttstock and folding carrying handle on top of the receiver. The flash hider of the Modelo C rifles set up to accept and launch NATO-standard rifle grenades. Most of the rifles issued to the magazine capacity of 20 rounds and made of steel, but 30 round magazines are also available.