I fed my K31 fireformed WW .284 Winchester brass. Actually, I ran it over a .308 expander ball, and loaded it with 4895 and a 150 gr. bullet. It shot REALLY well! Later on, I got some of the Hornady headstamped boxer primed 7.5 Swiss brass, and could not get the performance on paper from those loads that I was getting with .284 cases.
Performance is nearly identical to the .308, or 7.62 NATO, if you prefer.
The ONLY problem I had with it was at a "Vintage Military Rifle Match", and as the K31 ejects straight up, the brass (HOT brass) had an annoying habit of putting every other case down my back.
You will NOT find a faster-to-operate bolt gun. You will not likely find a military surplus weapon, especially at that price point, that will do what it will do on paper, and it will do whatever a .308 or maybe even the .30-06 will do.
If you want an eye opener, take a K31 and a Mosin out, put 'em on the bench, fill 'em full of GI fodder, and see which one you prefer! One in a thousand Mosin might shoot well, and I've yet to see one that'll keep up, consistently, with a K31. ALL Mosin's will pound you harder than the K31.
Don't know about now, but guns coming in a few years back usually had a piece of paper under the buttplate that had the previous (civilian) owner's name, and contact information on it. There were quite a few REALLY interesting conversations going back and forth between the new owners, and those fellas who were required by law to have one for defense of their nation.
