Just recently picked up a K31 rifle and ordered K31 specific dies for it from the CH4D company. Used brand new PPU brass which I naturally full length resized before chamfering the case mouths. Loaded up a moderate load using Hornady FMJBT bullets and IMR 4064.
Checked the runout on my RCBS concentricity gauge. All cartridges measured less than .001" runout and the majority were half that. Super good quality reloading dies. Rifle is a very good shooter, (1.5" at 100 yards).