As CaspA has said, you could put a real M134 in that sort of frame, but it would probably seriously injure the operator if they fired it like that.
Just to give you an idea of the thrust the M134 puts out...
A friend of mine has a minigun (actually two...one is for sale IF you have a LE love letter, an SOT and about $60,000) - anyway, his gun is mounted to a modified M63 mount with a bicycle seat for the operator. I estimate the mount at about 80-90 lbs. My friend is a fairly big guy - about 200-210 lbs. The minigun weighs about another 20 lbs. Figure about 300 lbs sans ammo, battery, control system, feed chute, etc. He set the weapon up on a spot of ground covered with rough gravel. With less than a 50rds in a test belt, the force of the weapon pushed the weight of the entire mount (with him sitting in it) across hard gravel backwards approximately one foot...and again, that was less than 50rds in a single burst pushing about 300 lbs. against a very high friction surface.
What do you think the same short burst would do a 175-200 lb man firing from the hip?