I have been doing a bit more digging into these pistols, asking other collectors for their opinions and looking more closely at the images. The first thing I can say is that there has been universal agreement that the pistol marked with 6⅓ mm is the same as the one pictured on the Swedish auction site, and has since been cleaned up and reblued.
Secondly, close inspection of one of the gun’s pictures on the Swedish site revealed partial lettering under the barrel which spell the word IMPORT. I have contacted Stroud Auctions, asking if there is any such lettering under the barrel of their gun, but I have not been able to get any response from them.






So this is my take on the 6⅓ mm pistol. This gun would most probably have started off as a war-years export from Germany to Sweden, as it is known that many were exported there up to 1944. I have copies of early 1940’s Swedish catalogues advertising them, but in .177 calibre only. The word IMPORT has the same meaning in Swedish as in English, and would serve the same role as the word FOREIGN found on many of our imports.
The calibre, expressed in the form “6⅓ “, is peculiarly German and is found in many vintage German catalogues, but I have never come across it in Swedish catalogues. It seems most likely therefore that the gun barrel was made and stamped in Germany, by Venuswaffenwerk, and the stamping has obviously been made with a purpose-made die. A Swedish company is unlikely to have any need to drill out a .177 barrel to such an odd calibre, and is also unlikely to have had access to such a specialist die. I can only assume that in the war years, Venuswaffenwerk were making do with whatever materials they could get for airgun production, which had to take second place to main weapons production, and was only tolerated to earn a bit of much needed foreign currency for the Reich. The 6⅓ mm calibre barrelling used on this Tell 3 pistol was just a result of expediency, making use of what happened to be available at a very difficult time. The pistol, perhaps part of a small batch, was shipped off to Sweden and then we know the rest of the story. I did ask the Stroud auctioneers if the barrels of their two pistols were rifled or smoothbore, but again, no response.

As far as the 6mm pistol is concerned I haven’t formed any conclusions, but Jimmie’s comments are interesting and food for thought.