I guess full auto mag dumps are the most accurate fire you can provide when the monsters only have 2 small areas vulnerable to damage. The short barrels were chosen because they have cool fireball flashes for effect. If you are going to take the time to teach your actors how to shoot movie guns, throw in a damn mag change once in a while. 30 years from now we will have an endless supply of ammo so we have that to look forward to.
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