If you have to encounter a venomous snake, a copperhead's the best one: they're the least likely to bite; if they do bite, they're the least likely to dump venom; if they do dump venom, they're the least likely to dump all the venom.
This accounts for the cowboy tales of shrugging it off to no ill-effect; just stupid, dumb luck.
But it's no joke if they dump the venom, some or all. Don't wait to see -- get emergency medical attention immediately for any person or animal bitten.
I've read that the coral snake is least likely to bite and it does have the shortest fangs. But if one tags you, it's bad news. They're sort of New World kraits, colorful bands, elapid venom and all.
I saw one just in time to avoid it in the woods and let it go, although I had a pistol. We were in wild country and no one else was likely to be by there soon. The bright colors helped me to see it in the leaves.
Also almost stepped on a water moccasin that was hiding under some dead grass by a stream. The landscaper at an apt. complex had cut the grass a day or so before and the snake was hiding there when I had to chase my daughter after she snitted off after a fight with her brother. The snake dived into the water just as I was about to step on it. They're usually more aggressive, and I was very lucky.
The moccasin and copperhead are both of the genus Agkistrodon, and the necrosis from a moccasin bite is even worse. The young of both look a lot alike, too.
Young snakes are more potent, drop-for-drop, so don't think they're innocuous because they're small.
I saw the post about getting within three feet of a snake before firing at it with small shot. I'm not comfortable being that close. They can move fast. And you don't know how big a snake you may need to shoot. I load normal bullets.
I suppose that if I might have to shoot one of those big Burmese pythons in Florida, I'd want a Plus P .38 or more.
I think more fatalities are caused in the USA by Western Diamondbacks than by any other snake. But that's in part because there are more bites by them. Some others are actually more dangerous if they happen to hit you.