I consider any gunfight to be a disaster.
I want to shoot him before he can get off a shot, justified by his attempting to do so. More likely, tho, he will have "only" a knife or a club, or force of numbers. So a lot of shots should not be needed.
"High-round gunfights" are vehemently to be avoided, regardless of what gun you are carrying. You aint a cop. Every rd fired, by you OR the bad guy, you can easily wind up being held responsible for. Mostly, tho, no shots need to be fired at all, or 1-2 misses suffice to run them off. Normally, the attacker does not have a gun. I have pointed guns at people several times. They all froze in their tracks. Any cop will tell you the same thing.
So, pretty much any pocket gun suffices, normally. I greatly prefer a Kahr CM9 to the .38 snub, tho, in case things get bad, and because it lies much "flatter" in my pocket holster. The .38 snub has minimal chances of expanding a hp in flesh. The 1300+ fps (from a 3" barrel) CorBon 9mm jhp does expand nicely, and it's got 400 ft lbs from the little 9.