Beretta PM12

Beretta PM12 Sub Machinegun

The Italian army was among the first people to use sub-machine guns, and Beretta the second people to make them. The Italians devised a very light Machine-gun firiing 9-mm pistol ammunition in 1917, but in its original form it was somewhat impractical. So Beretta took the basic receiver, barrel and mechanism, allied it to a conventional carbine stock, and produced the Beretta M1918 sub-machine gun. With one or two subsequent modifications this remained in Italian service right through World War II, but few people realized, since it looked like just another short rifle.

Post-war weapons

Tullo Marengoni, the Beretta designer who devised the M1918, subsequently developed a number of sub-machine guns following the M1918; these were very successful and efficient weapons. But in the early 1950s a new designer, Domenico Salza, took a fresh loo9k at the sub-machine gun idea and began putting together some experimental models. These led to the Model 12, which went into production in 1959 and was adopted by the Italian army in 1961.

The Model 12 was a very up-to-date design, employing stamped metal pressings which are spot-welded together to form the receiver, magazine housing, and trigger housing. The whole design was geared to make manufacture quick, cheap and easy to produce a reliable gun. In order to get as compact a weapon as possible, Salza adopted the 'overhung bolt' or 'telescoping bolt' idea; most of the length of the barrel lies inside the receiver, and the cylindrical bolt is hollowed out for much of its length so that when forward it encloses the rear of the barrel. The sides of the bolt are slotted so that the cartridge can be fed and the empty case ejected, and the cocking handle is fitted to its front end, protruding through a slot in the receiver.

The advantage of this 'telescoping bolt' design is that the gun's overall length is kept short, compared with the length of the barrel. In a conventional design the front of the bolt stops at the end of the barrel; there has to be a specific mass of bolt in order for the blowback system to work, and the bolt has to travel back a cert6ain distance in the receiver to absorb the recoil and have enough room to extract, eject and reload.

Telescoping bolt

Add all these together and you finish up with a rather long weapon, which is why conventional sub-machine guns of this sort ten to have short bearrells. But by telescoping the bolt around the barrel you can save length and keep a good long barrel that allows the cartridge to gain maximum velocity.

Another advantage claimed for this design is that the positioning of the barrel and bolt make for excellent balance, and it is quite easy to fire the M12 single-handed at full automatic without very much 'climb' of the muzzle.

The M12 had a pistol grip which carried a grip safety; this has to be squeezed by the firing hand before the bol is released, preventing accidental discharges. There was also a push-through safety catch above the grip which additionally locked the grip safety. Another push-through button above the trigger selected single shells or automatic fire. The magazine fitted into a housing just ahead of the trigger and a front grip gave a good holding position. There was a folding metal stock which lay alongside the receiver when folded.

Military and police use

The M12 sold well in the 1960s and was adopted by military and police forces all over the worlod, and in the mid-1970s the Model 12S appeared. Although this looks the same as the Model 12 there are some important improvements.

The first and most important change as iun the safety and selective-fire arrangements. Instead of two separate controls, a single rotary switch lever was placed on the left side of the receiver, giving safe/single shot/automatic in one movement. The grip safety was still fitted to the pistol grip, but the rest of the selection could be done with the thumb. The foresight was made adjustable for both elevation and windage;both sights were given stronger bases and better side protection; and the catch that holds the rear body cap in place was moved from the bottom of the receiver to the top, so that it could be operated more easily when stripping, and could be inspected easily to ensure that the cap was tight. The folding stock and the internal mechanism of the trigger were improved, and the exterior of the weapon was finished with a coating of epoxy resin instead of the earlier phosphate finish.

The Model 12S has replaced the earlier M12 in the Italian army and police, and is in use with several other armies around the world. It is also made under license in Brazil.

Added:  Monday, March 27, 2006
Reviewer:  Reviews
Score:
hits: 1108
Language: eng