Assuming one reloads enough to buy slips of 5000 primers and powder in 8 lb quantities, even the premium priced military sensitivity spec primers for gas guns are about $0.04/each (Federal GM205MAR or CCI #41 from Graf & Sons; this is with $8 shipping and $10 hazmat fee currently) and powder about 0.08 (H335; appropriate for a 0.07 cent bullet and assuming you got it in the same order as the primers so the hazmat is shared) then with a 0.07 cent bullet, you should be at 19 cents before counting brass amortization. If your brass is free, gathered from the range (frequently the case with .223/5.56 brass), then there is none. If you get ten reloads out of new Starline brass, you're adding about 0.02 to that price.