I would never fire a warning shot anyways, it gives away your position, tactically it does nothing for you other than you could go to jail if you only fired a warning shot and that was it. If its necessary to pull a gun, then it's probably a bad situation with no other peaceful retreats, then it's time to make the first shot count.
Russ, living out here, in a kind of "no man's land",[280 folks in town], most everyone has sufficient firepower, to at least run some delay action, until the Keystone Kops get here...Usually only 15 to 40 minutes away...[Last call to report a B&E...I timed it at 43 mins!]