thats an very interesting rifle, you had seen this post about the geco/kaba rifles? http://forums.nitroexpress.com/showflat.php?Cat=0&Number=206900&an=0&page=0#Post206900

its a more basic model but none the less very charming. probable made in Suhl/Zella Mehlis and the EK on the barrel is iirc this things for Erich Kelber a barrel maker in suhl.
I wonder about the 18,3gramm stamp on the receiver because only the 22,5 gramm bullet was ever used in the 10,75x57. could be the rifle was made by the same unknown firm who build also the higher grade Kaba sporting rifles.