This Drilling cofiguration was invented and initially protected by W.Collath in 1896. It allows to fit a practical 2 rifle – 1 shot barrel assembly into a standard drilling action bar that usually does not have enough space to allow for a fat shot barrel with thick walls that connects the top rifle barrels to the underlumps. After Collath's design protection expired, this design was copied by other German and Austrian gunmakers. Usually the second rifle barrel is at the top left to be served by the rear trigger. The bottom barrel, served by the front trigger, usually is used first and more often. A "left – right" bang-bang is needed less often, if the first shot is well aimed. The most often used first rifle barrel is deep in the action bar, close to hinge ad lockup. This reduces stress on the action. Such a barrel assembly may be fitted into any production line drilling action, without need for an extra-wide action bar. This helps to streamlie production and keeps cost down. In GDR times only double rifle drillings of such a configuration were available from "Merkel" and other Suhl makers. Disadvantages: Reloading is a tad slower as you have to reload the lower, less accessible barrel more often. Regulation is sligtly more difficult too as the rifle barrels are at a slant angle instead of horizontal or up-down.