Maloke , as I said it is realistic to have a fast shooting weapons in your project , but again as I said , people wont like to run out of ammo because they freaked when the zombie came out of nowhere and imagine they missed... I bet the military have much more advanced technologies than AK47 with its 10 shots per second (btw,not every one has 30 bullets in its magazine,some have 45,just a matter of teritory(where it was made)) and those advanced tech weapons shoot much faster , but it just isnt good for games...