The most weird feature of PP-90M1 is its charging system, which is made as abutton, located just above the muzzle. It had to be pressed with the finger (see arrow) to cock the gun. Not the safest way, if anyone will ask me.
Caliber: 9x19mm 7N21 and 7N31, compatible with all 9x19mm Luger/Parabellum ammo
Weight: ca 1.7 kg less magazine
Length (stock closed/open): 424 / 620 mm
Rate of fire: 500 rounds per minute
Magazine capacity: 32 rounds (box magazine) or 64 rounds (helical magazine)
Effective range: up to 200 meters
The PP-90M1 submachine gun is the latest development of the Tula-based famous KBP design bureau. It is a completely new development, despite its designation, that could misleadingly suggest that it is a derivative of the PP-90 and PP-90M folding clandestine machine guns. PP-90M1 could be described as a more modern rival to the "Bizon" PP-19 submachine gun,made in Izhevsk. It is intended to provide compact and lightweight police weapon that could lay serious amount of fire, thanks to its large-capacity helical magazine (similar in basic concept and design to "Bizon"and Calico submachine guns magazines). The most interesting part about PP-90M1 is, however, that it also could be fitted with adapter and then use typical box magazines, which are lighter, have slimmer profile and 1/2 capacity of standard helical magazine. It is not yet known if PP-90M1 is in use with any major law enforcement or security force in Russia.
Last autumn I had the chance to examine PP-90M1 in person, although not fired it. In my opinion, it is hardly worth a second look for a real buyer, and will remain here for the sake of curiosity. The weird charging system, slow disassembly and reassembly, poor fixed sights are the most notable features of this strange design, actually not typical for such respectable company as KBP.
PP-90M1 is a conventional blowback operated, selective fired machine gun. The gun housing is made entirely from plastic, including integral pistol handle and trigger guard. The top-folding buttstock is made from stamped steel. Safety / fire mode selector is located at the left side of the gun, above the trigger. The charging "button" is located just above the muzzle and should be pressed with one finger (not that easy to do so!) to retract the bolt. It is also unsafe, in my opinion, and mounting of silencer will interfere with charging, too. Weird! Another strange, if not weird, thing is the field stripping. To disassemble the PP-90M1, one must screw out the long disassembly screw, located above the magazine. This requires no tools, but can take about 20-30 seconds. When screw is gone, you then can took the barrel, bolt and return spring out of the gun by pulling it forward.
Feeding is from helical magazines of large capacity, or from typical box magazines, using detachable adapter, which also serves as a forearm. Helical magazines are made from plastic (mostly), while box magazines are made from sheet metal. The PP-90M1 is strong enough to routinely fire powerful Russian-made 9x19mm ammo with armour piercing bullets, 7N21 and 7N31, which is about 9mm +P+ or even +P++ class in the terms of barrel pressure. Any military or commercial 9x19mm ammo can be fired from PP-90M1 safely as well.