I know that it's a gimmick, but you just dont need that extra control for firearm weapons when you can both deadlift several tons, having MUSELS OF STIL and use a recoil dampening mechanism for the gun, like in the AA-12 shotgun.

EDIT: but yeah, reloading will be slower and you wont be able to chuck a grenade in a blink of the eye, even with straps and holsters. Still, not much of a tradeoff for having yet another reason to stick an extra bullet in their gullet.