Unlike APS universal automatic AFM-DT has a rifled barrel caliber 5.45 mm, with a pitch of rifling around 150 - 200 mm, and the depth of grooves about 1.5 - 2% of the diameter of the barrel (0.008 - 0.011 mm), which in addition to the use of special underwater cartridges satisfactorily stabilize the bullet staffing automata cartridge 5.45h39 mm.

Underwater cartridges are built on standard liner from 5.45h39 mm cartridges, allowing them to shoot from the same barrel as conventional 5.45-mm cartridges. Bullets underwater cartridges have an actual diameter of 5.45 mm (unlike bullets IPU cartridges having a diameter of 5.66 mm), allowing them to pass along the trunk AFM DT, without bumping into the rifling, followed by stabilization in the water column using the cavitation bubble generated in bullet moving in the water.

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