Yes, you can shoot 6.5 X 55mm Swedish ammo in your Norwegian Krag.
(BTW - Norway did not get its independence from Sweden until 1911. Their militaries used a common cartridge, but, different weapons).

Eventually, you will probably want to re-load the 6.5 X 55mm cartridge. Stay with milder loading data.

Norway was the last of three countries to adopt the Krag-Jorgensen (1894).

Denmark (1889) and the U.S.A. (1892) had adopted Krags earlier.
There are numerous differences between the Danish (8mm), U.S. (.30-40 cal.) and Norwegian (6.5mm) Krags.

Attached photos:

1. Model 1894 Norwegian Krag.

2. A British Lee-Enfield - Number 4, Mark I (.303 cal.), like your, Canadian Veteran, Uncle probably used.

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