When one of the characters screams and fires at the creature in the jungle, he fires three completely different guns in the same sequence. In the wide shots, he is carrying a full sized FN FAL rifle, in his medium closeups, he is firing some sort of wood stocked Submachinegun (Perhaps a Suomi, a Cristobal Mod 2, or a Beretta Mod 38), and in the extreme closeups, he is firing a Chinese Model of the AK47 (Type 56).
The special ops people are supposedly former Army Delta Force personnel, yet they continually mention Camp Pendleton - a Marine Corps base.