an austrian model of 1768 double stutzen, maybe a the only o/u combination gun ever used by the military https://www.waffengebraucht.at/waffen/mi...-m-1768--448169

this is a rifle - shotgun combination or better a combination of a jaeger rifle and a smmoothbore musket to shoot the bullet with the rifle when having the time to load or use the smoothbore when in need. this was the gun for the special border jaeger units on the southern border agains the turks, a very rare muzzle loader today.