5.45×18mm

5.45×18mm MPTs (7N7) is a Russian pistol cartridge. It is chambered in the PSM pistol and OTs-23 Drotik machine pistol.

It was designed in the Soviet Union in the early 1970s by  Antonina D. Denisova at the Precision Mechanical Engineering Central Research Institute (TsNIITochmash). The development was done in concert with that of the PSM.

The cartridge is designed to use light spitzer-pointed jacketed high velocity bullet. In terms of power, the bullet energy is stated to be up to 1.5 times that of the .25 ACP in a similar sized cartridge. More importantly, it is stated to be capable of penetrating 30–45 layers of Kevlar soft body armor followed by 10 to 15mm of solid pinewood at "realistic engagement distances".

Though the pistol was originally intended to be a pocket pistol for issue to high-ranking Soviet officers, it has reportedly found popularity amongst police and KGB officers as an easily concealed and suppressed operational pistol.