Only one that qualifies for most versatile is any revolver in .357 Magnum. The loads available for this gun are amazing when you include .38SP. My preference is a S&W 586, 4-incher. However, if you put a $400 max on it, you can find a strong Ruger GP100 for that money or an original Rossi before Taurus got'em. Sometimes, a blued Security Six can be had for that or less. I've killed everything from deer, wild hog, coyotes, down to bunnies with shot shells with the .357.
I even own an early Ruger Blackhawk in .357 which I used to hunt with. Great caliber.
I have the Taurus pt111 millennium g2, the Glock 17 an the Canik tp9sf paid less than $400 for each of them. I haven't had an issue with any of to speak of, only one I had was with aluminum case ammo in the Taurus. And that FTF an FTE with about 3 rounds.