Ok lets look at reality:
The US Special forces in the late 1970s did experiment with a handheld minigun but was too bulky, clumbersome, impossible to control and was pointless at the end.
At least with the pribor-3b, It lacks the rotating barrels that would get caught and tangle in debris etc, Lacks external power source, And lighter and less bulky to carry around. Would be easier to mass produce and maintain.
The point of the 3 barrels:
Higher chance of hitting target(Thats what 'Project SALVO' was all about) and increasing stopping power, Rapid fire without quick barrel heating/erosion,
Only drawback really would be ammo cost and recoil force, Still could be a useful weapon though.
Suppose it could be issued to SF Units, A particular squad member(A Meat-Head
)
Someone on another forum said it had problems with reloading, I say we send it down to H&K, They would solve its drawbacks, Well they did with the SA80.