If you mount the machine gun on the front rack then you'd have to put a couple wide belt pulleys on the top bar to run the ammo belt up to the front. Might be good, might need a little shield in front too so the hot spent casings bounce to the side not back up in your face as you ride. But then, as another poster pointed out, you'd be ready in seconds in case it's a "fast zombie" outbreak instead of those old slow zombies.