so I got the Nikolaus Dreyse ( nobilitation in 1864 than von Dreyse)Zündnadel fusilier rifle and a Franz von Dreyse( his son after 1867) needle fire double gun too.
you would say "stop" whats with the double gun here in the combination guns forum?
so lets take a look

caliber is 0,70"( prussian inch not imperial) Randschlußpatrone, maybe translatet as rim-end cartridge and meaning a needle fire paper cartridge with a massive breech end

this is an original cartridge

F(ranz).v. Dreyse Sömmerda

dont look like a shotgun foresight

have a rear sight too

whats this on the right barrel?

this double gun is or better was a combination gun with an interchangeable chamber. it was a combination gun because the rifled chamber is lost and the shotgun chamber is fix now because of corrosion. I am sure if it was possible to get the chamber piece out the last owner would have done this.

here you can see the chamber piece in the right barrel

the "rotation piece" makes an upside down paradox gun by giving a bullet a sharp spin in the beginning. the rifling diameter fits the shotgun barrel diameter and the roundball bullet is flying like a common rifle bullet than.

the big disatvantage of the dreyse gun is that have to loose five screws to get the barrel out of it.

very typical for dreyse guns is a hunting dog or a fox in silver on the gun

have laying around a 0,74" Dreyse double gun waiting for a new stock and restoration for many years now.
the 0,74" chamber takes 16 ga brass and shells without modification. they have a loose fit but with black powder loads I see no problem to shoot it. the Dreyse/RMS 1904(?) catalog have needle fire shotgun cartridge from 0,59" to 0,74" but I have only seen 0,70" and 0,74" guns till now. a hunter here have a 0,74" Dreyse gun that take 14 ga brass. have made ammo for him years ago when 14 ga greener police gun brass was available by OWS. I believe this gun was rechambered when the original ammo became obsolet but 14 ga shot shell are obsolete now also.

here with the double gun you see the common shotgun foresight

uncocking the needles, its easy to uncock and cock both with the thump in a moment

by pressing the trigger you can take the complete needle/spring unit out

the Dreyse guns together

side by side with the Dreyse rifle, diameter is very similar with 16,5 groove diameter for the rifle and 16,6mm for the shotgun barrels

20 ga magtech brass and plastic/paper shells dont realy fit into the chamber but the rim is not bad

rim dia. of the chamber is 19,45mm to 19,27mm Magtech brass, than 18,3mm to 17,8mm over 6mm - thats where the "Randschlußspiegel" is in the chamber
chamber going down than to 16,85mm and over the next 60mm down the 16,4mm
20 ga magtech brass is 17,56mm on the base and 17,18 o the neck. with a resizing die and anealed brass it would be easy to press it down. glue a big muzzle loader primer or a berdan primer inside on the ballon head primer pocket and reloading can start

here you see how the hooks holding the cartriges when the barrels going forward and to the right side. show it with 16 ga shells in the 0,74" double gun action