410 "Snake Charmer" and/or 357 with rat shot... wonderful things to (be)hold.
They will make a snake leak all over at the same time. AND... they are like N-weapons, granades & bellie rubbing... close does count.
I have used .38/.357 shot on rattlesnakes, and found it to be quite inadequate. Large holes in the pattern, not enough shot. .44/.45LC works perfectly though. Although I frequently advise first-handgun people to buy a .357 D.A. revolver, there are a lot of important things which they do not do well...and stopping dangerous game, including rattlers, tops the list.
The .410 is probably great though, and I am considering getting a Derringer for that load. Where I am, the chance of dangerous ricochet is high, or I would just use standard bullets on them, especially lead. This is why I favor revolvers for utility in the field. One can mix loads, and still have functional reliability.
BIG bore double action revolvers! I know several people who have and do successfully use other things, but most agree that the .44 and up d.a. is the best choice for unexpected threats.
Dangerous critter gun threads are so much fun. Thanks for your post.