PP-90M1 submachine gun
The idea to combine advantages of box and helical magazines in a single weapon has resulted in developing modular arms. The Tula Instrument Design Bureau has developed the PP-90M1 submachine gun (its design has nothing to do with that of the PP-90M submachine gun), chambered for powerful 9x19 mm 7N31 and 7N21 cartridges with enhanced-penetration bullets, as well as standard 9 mm Luger rounds.
The submachine gun is blowback-operated and features a magazine mounted in front of the logger guard. The barrel and the bolt assembly are separate units, with boll guides and the cartridge ejector mounted on the barrel. The recoiling boil produces almost no shock when it reaches its extreme rear point. This fact has allowed gunsmiths to use a plastic body, integrated with the pistol grip and the trigger guard, which reduced the weight and the cost of the submachine gun, increased its corrosion resistance, and shifted the centre-of-gravity forward The long firing cycle results in the best rate of fire and improves the weapon's stability, and thus, the accuracy of Ike. The breechblock lever is replaced with a very rare feature — the front end of the bolt assembly protruding from the body features a notch, which serves as a cocking button. In addition to reducing the dimensions of the weapon, it also increased the leak tightness of the body.
Field-stripped РР-90М1 submachine gun: 1 - body with the pistol grip, sights, the trigger assembly, and the butt-stock; 2 - barrel; 3 - recoil mechanism; 4 - boll; 5 - helical magazine
The hammer-type trigger assembly allows the submachine gun to conduct both single-shot and automatic fire. The weapon is fared by the rear sear. The manual safety/fire selector lever is mounted on the left over the trigger guard.
The submachine gun may be filled with a detachable plastic helical magazine or a metal double-column box magazine. The helical magazine is attached directly to the receiver and acts as the fore-grip, while the box magazine is inserted into a removable adapter fore-grip. As the submachine gun underwent improvements, the Tula Instrument Design Bureau decided to give up She adapter altogether, so now the submachine gun is only equipped with the helical magazine. The metal butt-stock folds up-and-over.
In 2005 designers demonstrated a PP-90M1 model with most of its plastic parts replaced with metal ones, and its pressed-steel butt-stock replaced with a skeleton-wire one. The helical magazine underwent certain modifications as well.
The 7N31 cartridge enables the submachine gun to effectively kill enemy manpower wearing body armour. This round, fired from the PP-90M1, penetrates an 8 mm thick steel plate at a range of up to 30 m, and a 5 mm thick steel plate at a range of up to 60 m.
PP-90M1 submachine gun with a box magazine