it's a burst mechanism, similar to 3 and 4 shot burst mechanisms in other rifles. i have never seen an an94, but would guess it is managed by a stepped cam.

the reason it is a 2-shot is because the initial fire rate is very high. the fast initial fire rate coupled with the recoil reducing counter weight masses in the weapon enable it to get off two shots before the balance of the rifle is upset by the recoil being transmitted back to the shooter. thus, the accuracy of the second shot is not affected by the first to the degree it would be in a conventional, non-balanced mechanism rifle.

after the initial burst is released, the rate of fire is reduced to a more managable figure.

I would worry about the cable and pulley system breaking down.. But I'm sure the ruskies have that solved...

ihzmash is using a perforated metat strip and cog/gear that engages the perforations to drive the balance mechanism on the 10x series. i'm certain it is a stronger, more simple design.

the an94 was the first successful machinegun of the shoulder-fired variety to utilize the balanced mechanism, and thus can be expected to be somewhat prototypical in its' features.

the kalashnikov, being a generation more advanced, can be expected to bring a higher degree of function, durability, maintanability and manufactureability to the genre.

the level of complexity of the device concerns me. after all, it is a machine and i prefer simple machines over complex machines when it comes down to brass tacks.