The Beretta Model 12S or Beretta M12S was redesigned as from the Beretta Model 12 in 1978 and was termed as "the Ultimate Submachine Gun" when released.
The Model 12s utilizes a 32-round box magazine, and comes chambered for the 9 mm x 19 NATO cartridge. The 12S uses the blowback principle, and is capable of either fully automatic or semi automatic fire.
A novel feature on the Beretta M12S is the grip safety, which locks the bolt and the trigger in the closed position, thus safeguarding against accidental discharge if the gun is dropped or if the grip is not held firmly. The fixed firing pin located on the face of the bolt can strike the primer solely when the cartridge is chambered fully, this feature also avoids accidental firing, according to its Beretta designers.
In The Field
The PM12S was also created with easy reassembly and field stripping in mind. These traits have been simplified and can be fully accomplished without tools. The M12S can be equipped with a full silencer, however this requires a slight modification of the small barrel by a competent gunsmith.
Without the silencer and additional optional features, the Beretta PM12S is made up of 84 distinct components.