Need?

Who cares about need.

When it comes right down to it, nobody needs more than one of most things.

But in reality, there is a limit to how much "you" (as in someone that is trying to limit someone else's access to something) should be allowed to limit said thing without both due process and significant cause. When something is a fundamental right (and anyone with multiple firearms is definitely of the mind that firearms are a natural extension of fundamental rights, so long as they exist at all), you, me, the government simply shouldn't be able to declare that anyone has to show need to exercise that right.

To the contrary, suppression of rights has to be done only under extreme and unusual circumstances.

Now, from your comment, I doubt you consider the right to defense as extending to firearms. That's fine, I'm not debating that by this comment (and won't, it bores the fuck out of me because nobody ever has anything new to bring to the debate). I'm just saying that if something is a right, placing your idea of need on it simply isn't acceptable.

A dozen, a hundred, a thousand, it doesn't matter. All that matters is that the right exists. And, in the US it is a specifically enumerated right. There's wiggle room on when rights can be curtailed, suppressed. We do it all the time. But it can't be done lightly, and shouldn't be based on some arbitrary, ill defined standard of need.

That being said, the role of a handgun vs a shotgun vs a rifle at least points to three use cases that can't be met by the others. Since different calibers of ammunition have discrete properties, it can also be said that significantly different rounds would fulfill different roles (you shoot a squirrel with a .50 cal, you ain't scraping up enough to roast). Just based on that concept, it would be easy to point to at least six different firearms being "needed" to fulfill roles.

If you have multiple people using the firearms, you can need different ones for each person.

So twelve? It really isn't that many. I've seen hunters that will regularly use at least twelve different rifles in a year, sometimes more, depending on how often they can find time to hunt. Ignoring any debate about hunting being something you or I support, it is a use case that is common enough to merit the term need when it comes to the tools used to do it.

Now me? I don't need that many. Not a hunter, don't compete in shooting sports, don't even target shoot as a regular hobby. But you sure as hell don't get to decide what I do and don't need. Nor does anyone else without the application of due process and just cause.