Isn't the whole discussion kind of pointless? Assuming that the OP is concerned about defending his home in the event of wide spread civil unrest?
95% of us live in wood frame houses with glass windows. This would quickly turn to swiss cheese in a fire fight.
We all had a good laugh and piled on the OP for his question. (myself included). But his question is totally valid for the casual shooter/ gun owner. Ammo is scarce and super expensive for what can be found. Assuming the OP has a couple of guns and is justifiably concerned about the post election insanity that could occur, how many rounds should he try to acquire?
I truly believe that if shit goes sideways enough that you need more than 1000 rounds because riots have broken out and houses are being torched, the National Guard will be patrolling the streets and Marshall law would be declared.
The NES crowd sees ammo differently than most groups because we actually shoot our guns occasionally. Hell, I've had range trips with newbies that we chewed through 500 rounds in no time, through a half a dozen guns. 10 - 30 rnd mags of 556 goes in the blink of an eye.
But the OP should also consider that if things really get bad, the ammo you have now could very well be all the ammo you will ever have a chance to buy, regardless of what you are willing to spend.