The best advice I ever heard and which I pass on now is,
get the best semi-auto military pattern rifle you can afford (AR-15, FN-FAL, Springfield M1A, etc.), learn to *shoot* it and stock up on enough ammo.
Barring that, a good lever-action rifle, and/or a scoped bolt-action rifle.
Keep “Imperial entanglements” to a minimum.
Not in Brooklyn
I refuse to buy anything, firearm or not, that I have to register.
Well, except for a car. That has some form of registry. Mainly because I’m hoping to get a band together when I move. But that’s a different story.