The M249 SAW (short for Squad Automatic Weapon) is an American adaptation of FN Herstal's Minimi light machine gun, chambered for NATO-standard 5.56x45mm ammunition. This belt-fed, gas-operated, open-bolt weapon fires at a rate of 800 rounds per minute, very fast.
In Thing-Thing 3, it can only be unlocked by gaining 50 kills in the Project 153 boss battle (after beating Vahl Dreig the first time), but it's not a very easy task. The weapon truly lives up to its high rate of fire, and is one of the most potent weapons in the game because of it. It also eats up ammo at a relatively fast pace, rivaled only by the Dual Micro Uzis.
- The M249 is one of only two belt-fed weapons featured throughout the main series, the other being the Heckler & Koch HK21.