Some people just lose all rationality when faced with a snake. I never understood the need to kill snakes. I've killed two or three where I didn't have much choice but have caught and released many times that. And, assuming your forced to kill one, using firearms just doesn't make much sense to me.
Using a firearm is not necessarily a bad idea (especially if an irrational fear of snakes precludes you from being able to be in direct contact with it, even with a stick) but trying to shoot a snake with a .22LR can be a tough shot. I keep a couple of boxes of
CCI shot shells on hand (.22LR and 40 S&W) just for snakes, although a 12ga target or bird shot round (#9 shot) is even more effective if noise is not an issue.
Jim