PP - 90 and PP - 90M submachine guns
The Tula Instrument Design Bureau demonstrated the PP-90 compact folding submachine gun in 1991, while in 1993 it developed its upgraded PP-90M version. The weapon is intended for special operations units and is designed for concealed carrying and surprise action.
In the folded configuration the PP-90M submachine gun could be mistaken for a 270x90x32 mm box. To prepare the weapon for action all that is required is to press a securing hook at one end, grasp the two halves and pull them apart. The weapon then hinges open, and the loaded magazine, inserted into a simple pressed pistol grip, and the hinged folding trigger guard snap down into place, as one half becomes a rudimentary butt-stock. The bolt is then cocked by being pulled back with the help of a hook protruding downward. The entire sequence, including cocking the bolt, takes only three to four seconds, depending on the qualification of the shooter.
The PP-90M operates on the blowback principle of the heavy bolt. The weapon is fired by the rear sear loaded by the mainspring, accommodated in the upper part of the bolt assembly, running over the barrel. A long bolt travel, a long cylindrical spiral spring with a great number of coils, and shots on the recovery ensure almost shock-free operation. The trigger assembly includes a manual safety/fire selector lever. When engaged the safety catch blocks the sear, and the bolt is held to the rear until the front and the rear ends of the receiver lock completely. When the fire selector is set to single-shot fire, the sear is held opposite the trigger by the mainspring, after a discharge the sear disengages from the trigger and is pulled forward by its spring. As a result the recoiling bolt cocks again and it is necessary to release and then pull the trigger again to fire the next shot. When the fire selector is set to automatic fire, the sear remains engaged with the logger and firing continues until the trigger is released or the magazine runs out of cartridges. The PP-90 model could only conduct automatic fire and was fitted with a safety catch.
The detachable box magazine is inserted into the pastel grip.
If aimed fire is required, the submachine gun is fitted with the pressed-steel folding foresight and fixed rear sight. If necessary, a laser target designator can be mounted between unfolded battle sights, L e. in the unfolded combat position only. The weapon can also be equipped with a suppressor.
Field-stripped PP-9GM submachine gun: 1 — bolt; 2 — mainspring; 3 — barrel with the receiver, sights, the trigger assembly, the safety/fire selector lever, the pistol grip, and the butt-stock; 4 — magazine.
PP 90M submachine gun in folded position