There are more guns in the country than there are people. And only 32% of American adults own guns. So if only a 1/3 of adults, who make up 2/3 of the population, own guns and there more guns than people, then the average gun owner owns 5 guns.
I would say owning 5 guns is close to hoarding but maybe not quite there. However, that’s the average. I know many gun owners who only have 1 or 2 guns. That means there are a lot of people who own a lot more than 5 guns.