Well, if Wiki said so..
Seriously, PPU ammo was the most affordable for years. Thousands of PPU cartridges were shot through M/94, 96 and 38, plus Ljungman.
VihtaVuory speaks of the 6.5x55 SKAN a boosted version of the 6.5x55.
PPU, Norma and S&B are perfectly suitable for the old rifle under CIP. Hornady is loaded BELOW CIP standards.