There could be no question of the development and mass production of the new patron Fedorov, and the designer adapted his rifle to an even weaker Japanese cartridge of
6.5 × 50 mm Arisaka with muzzle energy of 2615 J.
Arisak's cartridge when firing from the Fyodorov Machine gun had a
muzzle energy of 1960 J, and it was this value that was laid in the technical specification for a new intermediate cartridge for several variants of calibers - 5.6 mm, 6.5 mm and 7.62 mm, but for a shorter barrel. The Japanese cartridge was smaller than Fedorov's, and the rifles were fitted for it, inserting a special insert into the chamber.