In about 30 competitions in 10 years of Milshoots at EOSC, I have observed many K31's have placing in the top three, but only one Swedish Mauser has cracked the top three spots. Our competition requires unmodified rifles of WWII or earlier vintage and does not allow use of spotting scopes or spotters and it's 10 shots in three minutes at 100 and 200 yds. You would think that without scopes, that the quality of the iron sights would be a major factor in accuracy, and the K31's sights IMO, are inferior to the No4 MkI, P14/17, Garand, etc., but the K31 does as well or better than all of those fine rifles on a consistent basis.
This is hardly scientific, and the quality of the operator is a major factor in these shoots but I'd say the K31 is inherently more accurate than the Swedish Mauser.