single shot rifle probably in 8,15x46R, SN 559
notice the underlever is not made in the common way but in the style of a "english lever"
http://egun.de/market/item.php?id=5418944

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Drilling in 16/65 and 9,3x72R, SN 19449
the 65,5 cm long barrels made in 1926 and the original 70 cm long Drilling barrels in C.16 and 9,3x65R probably also in 1926 changed into double gun barrels without the rifle barrel for using the drilling as a double gun when hunting small game only.

very unique Collath Drilling SN 10344, 16ga and 11,15x65R
"Friedrich Jac. Bartels" on the barrels(dealer) and only blackpowder proof
http://www.guntrader.de/mediapool/75/759828/data/Jagdwaffen_12_M_rz_2015.pdf