In North America, it's sold as .25 ACP. In Europe, it's sold as 6.35mm.
25-125 USD
25-100 USD
I can find no listing for a J. Stevens model 80. There was, though, a model #83 bolt action made in various rimefire calibers including the .25 rimfire. This firearm was discontinued in about 1942. I find it difficult to believe that many .25 caliber models were made that late though. Unless you were to find an avid Stevens collector I doubt if you could get more than $300 for it as ammo is just about imposible to find.
50-160 USD
Clarke Stevens was born on September 25, 1915, in Bisbee, Arizona, USA.
These older stevens guns are valued at between 65-150 dollars.
These rifle,s range in price from 125 dollars for a gun with 60%original finish remaining up to 200 dollars for a gun with 90% original finish remaining on the gun.
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From what I havw found out, it is worth about $250. and is very hard to find any info on. More in books than on the internet.
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If we are talking about the model 15 favorite,which was a chambered in .22lr,.22WRF,or 25 or 32 rimfire?These rifles were made from 1915-1940.