Your selling price is changing. Post 1 you said $345 now you are saying $1040. What price are you selling it for?
But then again I don't even consider $1040 to be red flag issue. You must not shoot much or you would not be selling your ammunition (or a reloader). Using the previous base price of $10.00 a box of 50 rounds that comes out to about 5,200 rounds. For .223 / 5.56 at .30 cents each that is only 3,466 rounds. Many AR fans will tell you that it is not difficult to shoot up that much ammo.
There are several companies that primarily sell ammunition in bulk quantities. SGAmmo is one that I generally use. He may like to do a lot of shooting, is just stockpiling for future use or events or trying to beat shipping costs from buying over the Internet. I have a friend that only buys ammo with cash as he does not want businesses and the government to know what he is buying. You would get really excited if you saw my mancave. Heck I am about to order about $1,000 worth of just powder and primers.
You have three choices; sell all of it to one buyer, sell it by the individual box or just forget the idea.
It is a buyers market that may change a lot on November 8th.