My brother has snake loads in the first two chambers of the cylinders of his .44 spl just for this issue when up at the property. Me I don't worry about it as I have only seen one rattler in the seven years at the BOL. It was maybe 14" long but coiled for a fight.
I did not kill it but I did play with it using a long stick though.
In my current AO there is more problems with the damn raccoons than snakes this time of year. I went outside Thursday night and their was a pose of them trying to get my garbage can lid off. I grabbed a spade and killed one with one blow to the head. The others scattered so I went after them too. One actually had the balls to charge me with teeth blaring and hissing like a cat. Missed him with the spade though.
As I was blocking their exit they eventually jumped into the Sakonnet River that my house rest on the shore of. Went back and picked up dead Miss Raccoon and slung her into the Sakonnet for the crabs and lobster to nibble on.
I only mention this because of rabies will also be more prevalent post SHTF. Although none of these raccoons were rabid, I have shot some rabid ones along with skunks in my neighborhood. My liberal neighbors usually come and knock on my door asking me to shoot them when identified as such.