The weapon appears once in the campaign, in "Stronghold" in the hands of one of Makarov's men.
The PM-9 is unlocked at level 56, sporting a 32-round magazine. The PM-9 has the fastest fire rate of any automatic weapon in the game at 1111 rpm, making the weapon very effective in close quarters, featuring decent enough power. However, the PM-9 has a slow reload time and limited range both of which can be partially cured by Sleight of Hand and Range, respectively.
Pairing Rapid Fire, Extended Mags and Steady Aim, is one of the most effective setups for the PM-9. Rapid Fire will bolster the PM-9's performance at close range and gives the PM-9 an unmatched rate of fire. Combined with the three-hit-kill and reliable hip-fire at close range, the PM-9 is capable of killing multiple opponents very quickly. Extended Mags will partially cure the issues of the gun burning through the player's ammunition quickly and its slow reload time.
If a player wants to employ the PM-9 in a traditional submachine gun role, the Kick Proficiency reduces the recoil to very manageable levels.The iron sights can be obstructive to some players, so one may one to equip a Red Dot Sight or Holographic Sight. The muzzle flash of the PM-9 can also be a nuisance, so equipping a Suppressor will eliminate the muzzle flash entirely.
With Rapid Fire, the PM-9 statistically becomes the most powerful submachine gun in the game and is extremely effective within the short range the weapon is suited for. Despite the high power at close ranges, the PM-9 still suffers from limited range, poor accuracy at longer ranges, and a slow reload time, weaknesses of which can be cured by perks and proficiencies chosen at the players discretion.
Infinity Ward has released a hotfix that has decreased the recoil of the PM-9 drastically to make it much more on par with the PP90M1. The recoil profile after the update appears to be similar to the Mini Uzi from Call of Duty: Modern Warfare 2.
- Red Dot Sight - Unlocked at weapon level 2.
- Silencer - Unlocked at weapon level 5.
- Rapid Fire - Unlocked at weapon level 11.
- ACOG Scope - Unlocked at weapon level 16.
- Holographic Sight - Unlocked at weapon level 19.
- HAMR Scope - Unlocked at weapon level 22.
- Extended Mags - Unlocked at weapon level 24.
- Thermal Scope - Unlocked at weapon level 26.
- Kick - Unlocked at weapon level 4.
- Range - Unlocked at weapon level 9.
- Attachments - Unlocked at weapon level 12.
- Focus - Unlocked at weapon level 15.
- Melee - Unlocked at weapon level 21.
- Stability - unlocked at weapon level 28.
The PM-9 is available in Survival Mode at level 23 and costs $2000. The PM-9 is also used by Claymore Experts. The PM-9 is highly effective in close quarters, but the recoil and the reload time lessens the weapon's potential, as well as the late availability of Sleight of Hand.
- Although the weapon has a foregrip, it is never seen used.
- The PM-9 has a reused reload animation and sound identical to the Mini-Uzi.
- The PM-9 has a fingerprint on the back, like the Mini-Uzi from Call of Duty 4: Modern Warfare.
- On the Nintendo Wii version, the PM-9 reuses the Mini-Uzi's firing sound.
- The PM-9 is held by one hand in first-person, but held with two hands in third-person.
- The PM-9 has one of the highest base fire rate of any automatic weapon in the Modern Warfare series, only outperformed by the G18 and Vector, respectively.
- Like the Mini-Uzi, MAC11, Spectre and the Uzi, attaching a sight will make the hand clip through it during an empty reload.
- The PM-9, along with the MP5 and the UMP45, are the first submachine guns in Call of Duty history to receive an increase to their effectiveness.
- In "Stronghold" the PM-9 reuses the MP9's firing sound.
- When out of ammo, the player will switch to the PM-9 faster. This also applies for most other submachine guns.