No, Raimey, this is not Roehmer's patent mentioned before, as the drilling shown by ydduit has a selector slide alongside the front trigger. The verbal description of DRP 72583 does not mention such a slide. In fact the Roehmer design was meant to avoid any seperate barrel selector, be it a slide or lever. The barrel is selected by setting the front trigger by pushing it forward. If unset it fires the right shot barrel, if set the rifle barrel.