.366 TKM Overview .366 TKM  is a rifle cartridge developed from the Soviet 7.62x39mm. .366 TKM was developed for the  Russian civilian market, where smoothbore firearms are considered shotguns. Despite being a smoothbore cartridge it is still very capable, some loading such as the Deri and Geksa loads outperform 7.62x39 greatly. Stats Ammunition Type Damage Bullet Velocity (m/s) Barrier Penetration Armor Piercing Deri 10 610 1.85 4 EKO 9.2 770 2.5 4 Geksa 11.2 550 1.15 4 FMJ 9.6 580 2.3 4 Birdshot 2.4x85 240 0.3 0 Note: Barrier penetration represents the rounds ability to go through walls and barriers. Armor piercing represents the rounds ability to penetrate body armor plates.