These were one of the most accurate factory rimfires built in their day. They were built by Voere of Germany then imported into the US. A Company out of Sequin TX, owned by George Kleinguenther known for muzzle breaks, would take these rifles and accurize them. He also smithed their centerfire rifles. The rimfires came with a guaranteed accuracy of 1/2" five round group @ 50yds.
The K22 bring over $1000 and many times pushing $1500. You can still buy magazines from Germany (at least you could a while back) along with the double set triggers many came with. KDF was later sold to Mauser who produced them for a while. They called the Mauser 201.
They built a standard version with a birch stock and a deluxe version with a walnut stock and fore end cap. Yours looks to be the birch model but the photo isn't clear enough on my computer to tell. Both models had the 1/2" guarantee.

I've had KDF K22's since the late 1970's and have a Mauser 201.

Here's the Mauser version.
[Linked Image from i.imgur.com]

[Linked Image from i.imgur.com]