classic and very old "double rifle" for european big game hunting
of course not a pin fire as described but a needle fire, use a paper cartridge with metall base and round ball. I believe that the rifling chambers are removeable but fixed now with rust
measured 18mm will be a 0,74" dreyse needle fire cartridge

Hermann Historica München Lot Nr.2356

"A pin-fire double-barrelled gun with rifled chambers,

F. v. Dreyse. 18 mm calibre, no. 15269. Fixed rear sight and nickel-silver front sight. Mirror-like bores without rifling. The bullet spin is brought about by the rifling within the chambers. Barrel surfaces lightly reworked and newly finished. Lever action which swings barrels to the right for loading. The company name on barrel inlaid with silver "F. v. Dreyse". Locks with fine silver wire inlay. Iron furniture with ornamental and flower engraving. Selected walnut stock with fine chequering, a little chip on the left side has been professionally restored. Horn trigger guard. Length 115 cm.
The principle of rifled chambers was meant to protect the barrels from wear and soiling, did, however, not gain acceptance. Cf. Hermann Historica, 52nd auction, lot 1332. Length 115 cm.
With two rotating chambers of utmost rarity. "