Please provide some numerical proof of this, it sounds like a lie.
Focus on the changes suggested and reason behind it and not an examples given to explain it.
(but since you ask an LMG34 in the hands of pathfinders get more range (with vet) something the weapon not designed for, or in hands of 6 men squad cheap squads the weapon makes the squad too powerful)
as another example FJ gain very little by picking up a BAR.