As ini .25 ACP? Never even heard of them. They would have, like, 20 pellets? .22LR shotshells are less than stellar performance outside of 20' through a rifle. .25 ACP out of a 1 1/2" barrel will yield an effective range of about, contact range. The rodents will not sit still that long and You probably do not want to get that close to a venomous snake.
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"Robo is right" Fuzzball