The PP-91 Kedr SMG was developed in the early 90's by the order of Ministry of Internal Affairs and is now produced at Ziatoust machinery plant (Zlatoustovvskiy Mashinostroitelnyl Zavod ZMZ). At the moment, it is a service weapon of almost all Russian law enforcement forces.
While the PP-91 Kedr 9x18PM SMG can hold 9x18 mm PM PMM ammunition in its magazine, it can not fire it.
Better shoot when in a prone position, because the gun is way more accurate and its easier to kill someone on range.
Trivia
The PP-91 "Kedr" is present in Escape from Tarkov's predecessor, Contract Wars, a PvP multiplayer game also by Battlestate Games, as a tier 1 submachine gun.