Question: "Yes, but who carries rat shot around for reloading in their gun for when they see a snake in a public place?"
I do.

Not necessarily for use in a public place, but quite commonly the 6'th hole in Bianchi Speed Strip in my left pocket includes a CCI .38 shot load. Have keyed one up on several occasions in j-frames to dispatch copperheads, rats and rattlers. And wounded quailie birds that want to play hide and seek in the bush.