I guess I missed the boat by not getting one when they were cheaper. I too have noticed that many of them look like crud. It’s good to know that most are probably still mechanically sound, even though they might not look so good.
What do you think of this one?
http://www.impactguns.com/store/MK31-DSCW.html
What about the availability of ammo?
Ammo, I see hunting ammo made by a Serbian group called 'Partisan' being sold at gun shows or you can load your own, Huntington's of California has dies and new brass ( http://www.huntingtons.com/cases_graf.html ), the K31 caliber is called 7.5x55 for some reason despite the K31 being basically a 308 caliber rifle.
Again the overall cartridge length given in books is for that Swiss fmj bullet and is about a whole quarter inch wrong for normal 308 hunting bullets. You can load those Graf cases with ordinary Sierra or whatever 308 168gr hunting bullets but you simply walk the die in a turn or two at a time until you get a cartridge that the bolt closes over easily, and that's your real cartridge length.
One other thing, another BIG difference between the K31 and any sort of Mauser ias that there has never been a reasonable way to put a scope on old Mausers while there is a simple adapter for scopes for the K31 which goes in in five minutes.