a friend was selling his bügelspanner and this was offered me to be a 4,5mm or .17 caliber.
thought its fine because I have a lot of 4,5 mm pellets and so bought it but the 4,5 mm pellet fall through. it ends to be a 5,0 mm airgun, take it anyway. I have seen maybe 3 airgun of this maker, all the same.
we know its not made by Will http://forums.nitroexpress.com/showflat.php?Cat=0&Number=351200&an=0&page=1#Post351200 or Manteufel https://forum.vintageairgunsgallery.com/reinhold-manteuffel-co/manteuffel-1936-catalogue/
in Zehla Mehlis.
It was maybe another small firm in Zella Mehlis in the 1920s making this one.

it was build as a airgun for shooting gallerys. the gun was never blued, the action like usuals nickel plated but the barrel white and it looks like laquered agaist rust. most of the nickel and lacquer was gone and there was rust here and there. I checked the barrel carefull for traces of blueing but nothing. maybe it was made this way to safe money in the not so golden 1920s.the sights had a rest of black colour but his could be made later, I blued the sights now. clean the gun and laquered it, the wood get linseed oil

you see the rest of the nickel plating here and there

not anyone having a 5,0 mm airgun

its not the quality of my prewar Oskar Will but this a class of its own anyway

4,5mm, 5,0mm, 5,5mm, 6,35mm, 7,62mm

the H&N pellet unsized

the H&N pellet sized in the barel before to 5,03 mm
better but not good

the JSB pellet unsized

the JSB and the Händler&Natermann pellet

we know that this smooth bore airguns shooting better with the original spitzer bullet than modern pellets. with pellets you have allways some flying in strange directions.

the bore here is 5,03 mm, the H&N pellet measure on the head 4,91 mm, on the hollow base 5,24. the JSB pellet measure 5,04 on the head and 5,25mm on the base and this is maybe the reason it shoots much better. the head of the H&N pellet is much undersized in the barrel, looks also like some of the pellets make keyholes.
have to made a 5,03 mm sizing die, oversized pellets eat up to 20 feet a second from velocity because of higher friction.