In the seven plus years at my place in the hills I've had to kill 17 rattlesnakes that were just too close to the house and pets. All were shot with .22 LR shot shells (CCI and others) out of a JC Higgins revolver with a 6 inch barrel. Twice I had to make a second shot because my aim was off, (there was no safety issue). These snakes ranged from approximately 1 foot to 4 1/2 feet. Maybe my snakes die easier but I see no reason for me to go up in caliber or noise level.