Designed to replace the aging Soviet Tulsky Tokarev TT-30 and TT-33 sidearms, the Makarov used a new cartridge: the 9x18mm (in fact 9.25x18mm) cartridge as opposed to the 7.62x25mm cartridge. Under the project leadership of Nikolay Fyodorovich Makarov, it became the Soviet Union's standard military sidearm from 1951-1991. The Makarov is a popular self-defense pistol because of its simplicity, economy, ease of manufacture, light weight and reasonable stopping power.
The Makarov is the standard issue sidearm for the Military and rookie Duty members, and it is widely used by rookie Loners, Bandits and Renegades. The weapon is exceptionally light and durable, but lacks considerable stopping power and is not very accurate.
The PM is reliable and very light, although it has low damage and accuracy. It is moderately effective against unarmored foes, but it is not in any way ideal for combat and you'll want to swap it out for a Fort-12 or some 9x19mm FMJ pistol the first chance you get. The weapon uses the 9x18mm FMJ.
Wolf gives you one at the beginning of the game, along with some spare ammunition. Otherwise it can be found almost anywhere in the Zone, as it is commonly carried by Loners, Bandits, Zombified Stalkers, and rookies of many factions.
The PM is now reasonably powerful and can rival the performance of some 9x19mm pistols, as it's cheap to maintain and most upgrades cost less than 200 rubles, making it more useful later in the game than in Shadow of Chernobyl.
The PM is given by Docent Suslov along with some other equipment. The weapon is bought from every trader of all factions and held by rookie loners, bandits, Clear Sky members, military soldiers and Duty stalkers. Overall the weapon is pretty widespread and it's very easy to acquire one.
Its grip is also changed from Shadow of Chernobyl, now its grip has a finish not unlike bakelite, while in Shadow of Chernobyl its grip is made of dark polymer.
In Call of Pripyat, the PMm is stats-wise roughly the same as its Clear Sky incarnation, being far from the best but not a complete waste either. The most notable thing about it is the fact that loners, bandits and zombified stalkers (previously all common users of the PMm) have all adopted the Kora-919 as a rather common sidearm alongside the PMm, making the latter rarer albeit still plentiful.
The player's starting weapon is a unique PM, the "Ceremonial PMm".