Nah that's all Hollywood and will stay all Hollywood. Can you imagine schlepping around that much steel, that eats that much brass, and needs a car battery connected to do it? That high a rate of fire is a liability if you're not in a vehicle with deep mags. You'd need 5 or 6 Jesse Venturas just to carry the ammo, and it would provide roughly 1-2 min of shooting time.
Closest you can get to that would probably be an Ironman like backpack system but a gun with a much lower rate of fire, something air cooled and recoil operated. Like this 1919 maybe.
That 30mm is just a single shot rifle. Probably like other huge novelty cannons where you have to attach the base of the cartridge to the face of the bolt, then insert both slowly into the chamber. There
is a need for anti material rifles, but 30mm seems excessive. I think General Dynamics made a 20 or 25mm one awhile back, 4 round magazine I want to say. More of a proof of concept, I don't think they were ever adopted by any group. Now you can just send a drone and stay far enough away to not die.