RIA T40

"Experimental Thermal variant on the RIA 40, the T40 has reinforced barrels and modified thermal rounds for increased kill power."

-Official Description

The RIA T40 is a high-powered thermal LMG. It has a decent rate of fire and high damage (including its DoT). This LMG excels at torching mid sized-large hordes of zombies, and is absolutely devastating while riding the Ice Station Truck. While the T40 is not the best boss-killer due to it's large movement penalty, it's a superb weapon overall.

The T40 is basically a LMG variant of the RIA 20 Striker, and, in fact, even has 2 red stripes on the standard version's clip, just like the Striker.

Triva

 * As with the RIA T7, the "T" in "T40" most likely stands for "Thermal".