The only place I've heard complaints about the remote controlled machine gun, is right here on Sherdog.
Breaking Bad has never been strict on ultra-realism, even in the 1st season. Hydrochloric Acid doesn't eat through flesh and bathtubs like it does in Alien, or even remotely close to as it does in the show.
And remember that scene when Walt goes to see Tuco and throws the 'not meth' on the ground, causes a large 'explosion' that blew out the building's windows and no one was injured? Bullshit. There's no powder that can blow up upon hard impact of a surface, and even if it could the 'explosion' would have resulted in fatalities of everyone in the room - especially Walt.
In other words, scientific/contraption realism is about as important in Breaking Bad as how dragon fire causes everything to explode in Game of Thrones.