As a battle rifle, well I just don't know how well the K31 would have turned out. It shows expensive machining and is complicated. It would have been hard to create new production lines for the things, and a lot of people are just not mechanically minded enough to handle the bolt assembly/disassembly.
However, as a military surplus rifle in the hands of Civilians, it is one of the best. The level of precision that the Swiss built these rifles to is just unbelievable.
Two of my K31’s have mis matching bolts. A pre war rifle, its bolt matches the receiver. I was told that bolts are totally interchangeable across the production of these rifles, and based on comparing fired case measurements, it seems to be true. This is incredible level of precision from 1931 till the late fifties, across 900,000 rifles.
These rifles are the most accurate military surplus rifles I have shot, if they had windage adjustable rear sights, they would out shoot my best Springfield rifles in a target match.
The cartridge is an excellent design. It is hard to believe that it was designed around 1888. The rim is thick, so it would have made an excellent semi automatic cartridge, and it is not that much longer than a 308. It is just between a 308 and 30-06 in power. Which makes it an excellent round. If the US had copied it back then, maybe we would still have an effective round in our military rifles, instead of that .223.
It does eject up straight, which is not problem with irons, but I don’t know if that will cause a problem with a scope.