As a Native Norwegian, I agree that "Gevär" in Swedish, and "Gevær" in Norwegain, means "long shoulder gun" and not rifle in Scandinavian.

We have separate Words for shotgun, rifle, pistol and revolver, and the word gun simply cannot be translated directly.
When trying to translate "gun", the best we have is "skytevåpen"(Norwegian) and "skjutvapen"(Swedish), both meaning "shooting weapon"