But maybe the original poster had more than just one battle in mind.
He who shoots first and often wins.
A shotgun often wins such arguments, which is why the US MArines carry them in close combat. A group of 6 or 7 tangos standing together at 50 yards can be taken down with two shots of 12 ga OO buck. And when others come to get the wounded in the dark, do it again, but from a different position.
I could see working through 250 rounds that way over a few weeks or so.
I had more than one firefight in mind too.I would envision most shoot-outs using a shotgun wouldn”t go past 15 or 20 rounds.On our own out here in the country I don’t know how long we would last or how the threats would be presented.One or two hostiles at a time or maybe 10 or more.I’m fairly proficient with all my weapons,but having no intel for threat assessment would suck.