http://mwo.smurfy-net.de/mechlab#i=18&l=1c81890280c3514c1826a5133d930dae0c5cfd33 The max range of all weapons on the "Thirteen Fifty" is 1350 meters. It packs 18 double heatsinks to compensate for ghost heat. Mainly designed to take quick (for an atlas) pot shots at range (and to fullfill my dream of 4X ERLLas contained solely in the arms of a mech... you could do it on a ON1-K but... Atlas man... Atlas).
I'm not sure if I would play this build. It definitely has Long range firepower, but what if you get caught in close range? What if your Arms get destroyed? What if it comes to an Atlas Vs Atlas Fight?