Death's Head Immolator. Gimmick is to critfish, stack burn through Bonus Damage, and do so from out of LOS.

The base build requires DH3, Pegasus 1. You use the Railgun on the heavy mount to build heat, and a Smartgun on the main mount as your damage dealer. Smartgun is a rifle weapon that's accurate, smart, and seeking, meaning you can hit anything in a bubble of 15 hexes, provided you can trace a path, and ignore cover.

For talents you'll need, at minimum, Crack Shot II, Walking Armory II, Nuclear Cavalier II. At LL3, you get the Overpower Caliber core bonus and stick it on the Smartgun.

Now, Walking Armory II gives you Hellfire Rounds. When used on a Main weapon, all bonus damage becomes Burn.

With OpCal, Nuclear Cavalier (while in the DZ), and Crack Shot, you deal 3d6 bonus damage. With Hunter Lock from Pegasus 1 you can add +3 bonus damage. With Hellfire Rounds, it all becomes burn. With DH's traits, you regularly crit, making it that much deadlier.

As you level up, you can do some control by using Jager Rounds (imposes prone) and Crack Shot III (save or be immobilized).