I am not disagreeing with anything that has been said.

I believe the following to be true:

Swedish 6.5X55mm military ammo is usually corrosive, Berdan primed, and likely develops higher pressures than the ammo that Norway loaded for their Krag rifles.

Cartridge brass gets more brittle with age. Most of the Swedish military surplus ammo in circulation, no matter how clean, is 50 to 60 plus years old. (A failed rimless case allows high pressure gases to more readily escape into the action than a rimmed-case).

The 6.5X55mm cartridge is a dream to reload. Brass, projectiles, Dies, propellants, and data, is readily available. It is easy to make ammo better tailored for a Norwegian Krag.

"Ya pays your money and ya votes your choice".

(p.s. - I don't hesitate to shoot U.S. GI .30-06 ammo, made in the late 1960's, in my M1 Garand or '03-A3. But, that is a different 'animal' and not relevant to the original question).