In this video hickok45 tries very hard not to call .410 revolvers a dumb/silly gimmick. It’s hard to deny that they are fun guns, though. For protection, well, keep ’em loaded with .45 .44.
There are a few buck and buck ‘n’ ball ammo .410 loads that are specialized for these handguns but they still barely match .38 Special in terms of energy and offer minimum expansion.
There is one load, though, that’s a little different. If you absolutely have to carry a Judge or a Governor for self-defense, you might want to look into this Lehigh Defense stuff.
Penetration isn’t great but yeesh, that expansion and energy transfer is fantastic.