An A-10’s GAU-8 gun fires 3900 rounds per minute, and the A-10 can carry 1350 rounds. Send a few A-10’s out for close air support, mand a lot of bullets are going to get used up.
A-10’s do not use small arms ammunition. By a long shot.
Why is it necessarily a bad ratio?
250,000 rounds of 5.56 costs what, $100,000? Probably more like $50,000; you can get it almost that cheaply per round in smaller amounts at a gun store and I assume the US Department of Defense gets pretty good volume discounts on common NATO stuff like 5.56 and 7.62 rounds. $50,000 to kill an enemy isn’t too bad, really. Okay, 5.56 is the cheapest small arms ammo there is but 7.62 can’t be that much more. As the lethality of weapons systems go that is actually not bad as compared to a B-2, which would have to kill at least twenty thousand enemies to achieve the same kill-to-cost ration (and to be honest I am guessing low.)
If you’re a Western country with lots of money, throwing rounds by the zillion at the enemy to kill them and save your own men is a good tradeoff. If you could just buy enemy deaths for $50,000 a head, you could kill every single ISIS combatant for what the US DND spends on defense in one or two days.
I think you’re being too defensive. Nobody has said it’s a bad ratio. Do you think it is a bad ratio?
But it doesn’t answer the question: how many rounds are spent in combat?