From their website:
Operating independently, Khador’s senior Widowmaker marksmen move unobserved across the battlefield. The expert sharpshooters are equipped with the prized Vanar Liberator rifle. The Liberator weighs a full twenty pounds, nearly twice the weight of the standard hunting rifles issued to Widowmaker units. Capable of tearing through plate armor, Liberator rounds are as accurate as they are lethal in the hands of a Widowmaker marksman.