My Finn also seems to prefer Russian light ball for milsurp ammo. But my reloads are more accurate.
Rifle: 1944 VKT M39, iron sights
Range: 50 Yards, Temp 77, light breezes
Two groups of 5 each for ten total shots on target
First up, Czech Silvertip 147 grain. The two high shots were with an absolutely cold barrel, they came down after them.
Next up, Bulgarian Heavy Ball, don't remember how many grains the bullets were..yellow tips.
Then, Russian light ball, 147 grain.
Last of course, my reloads. JMS brass, 147 grain FMJBT's 49 grains of H4895, Win LR primers.