The hardest two items to making your own, is the primer and the smokeless powder. Blackpowder can be made in the kitchen with normally found items, but black will tear a semi-auto up pretty quick... Priming agents are just really dangerous to make and handle, plus thier composition is much harder to obtain.

I know the lowly 12 guage pump isn't a proper combat weapon, but it would handle the black powder just fine. The projectiles can be found in the garage or on the ground, and the wadding can be made from old T-shirts... but again you need primers, and hulls... although in a pinch you could come up with a workable hull....

The idea of a home level reloading and more deeply ammo making facilities has much merit, but many obstacles too....

The ammo problem is here too, I've seen guys argue about who was going to get the last box of 9mm ammo at the local Walmart....