 FAKE: During the opening credits, several of the men in snow  camouflage have impulse amplifiers on their assault rifles. Impulse  amplifier is a device used with certain types of training ammo to  ensure the gun keeps working, and also to crush the wooden practice  "bullet" into harmless sawdust. It blocks the barrel of a gun,  making it unable to fire live ammo when in use (and is thus used as  a safety measure in non