Factual error: In the boat-stealing scene, when the machine gunner fires a burst of blanks out of the M60 at the Cajuns, the weapon functions perfectly. However, the muzzle is bare. When firing with blanks, weapons have to have metal pieces called blank adaptors screwed into the muzzle to keep enough gas inside the weapon to cycle the bolt. Without one, the M60 would fire one round and stop.
Continuity mistake: One member of the Guard has brought live ammo. He loads them into an M-16 magazine which holds 20 rounds. Later he is discovered to have these rounds and they are taken away and distributed to the men. There are eight men and twenty rounds of ammo yet they seem to have a never ending magazine while they are shooting at the Cajuns. They can't be continuing to fire their blanks - it's impossible to fire a magazine with both live and blank rounds. If the weapon was equipped for blank firing (with a blank adaptor) and you fired a live round the weapon would explode. If you fired a blank without the adaptor it would fire one round and stop.