Two things,
1)Norway has a vastly different culture than the United States.
2)Norway is bordered by by Sweden and Finland, the United States of bordered by MEXICO so for every gun they picked up in the US, 3 would makes it way across the border to be sold here. And to be honest, we have enough, do-it-yourself people here that they could and would start making their own due to statement #1.
With which I leave you with...
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Mod Edit: No meme images please.