RK,
Pistol for snakes is OK! You just need to use the proper caliber and loads... .45 shotloads do a FINE job.
But where firearms and snakes are concerned... nothing beats a shotgun in ANY guage...
I used to know a young soldier from Tennessee or Arkansas that carried a military surplus machette in the turnk of his car. He could walk up to any snake and remove the head in one swoop... He never cut off more than about 2 inches, and I never saw him miss.
ME? I rely on heartier methods that involve a little more distance and a loud bang, -OR- as indicated above... a riding mower with the blade engaged and throttle maxed out.