Das Panzer Gewehre

They move with precision and speed taking advantageous positions be it in the crumbling infrastructure of war-torn towns or the vast landscape surrounding it. These soldiers are given a single order, "Do not let any vehicle or armor make it to the frontlines."  These units are often paired with infantry.  The only known threat to these men is their focus on ranged combat, and while they no doubt carry sidearms, their primary form of combat is ranged meaning should infantry get close they will attempt to fall back to advantageous positions.
Certain special Panzer Gewher units exist that use their modified T-Geweher(tankgeweher) able to fire a magic missile capable of penetrating some of the strongest armor employed by the allied nations. Due to their exceedingly difficult training and special equipment only five of these squads have been confirmed to exist by English intelligence operatives.

The makers of the gun were inspired by weapons used to hunt African big game, like the Elephant gun. The Mauser Company responded with the 13mm T-gewehr and began production at Oberndorf am Neckar in May 1917.  Due to their high production price and strict training required to use them very few have rolled off the line and those that have were issued to specially raised anti-tank detachments.