Just as the Dimensional Engine supplanted the fission reactor, the DTR will eventually replace the D-Engine. Once they iron out the little bugs.
The Langdon Ballistics company has a short and muddled past of producing shoddy and cheap weapons. Stocks are made of orange plastic with black paint coverings, and metal components of the weapons they make are typically low cost alloys. Their most famous weapon is the L-12 Scatter Rifle, a fairly high power large bore shotgun. It is easily recognized by its orange stock and pronounced ammo clip.