Every rifle in the world. (I'm not going to fall for this trick again.)
It doesn't matter how scary, ugly, uncomfortable, or inconvenient self defense can be. Like it or not, you will never, ever be relieved of your duty and responsibility to defend your life, your family, your country and your freedom.
How much ammo do I need? Enough to last me the rest of my life, and then lot more for later.
The government does not come knocking at your door. It comes knocking down your door.