Truth to tell, I'm guessing there are two factors here with satisfaction with these shot shell loads from handguns. First is where does the shot land ... where does the center of the shot load actually land? A head shot is always, always! going to be more effective on a snake. And heavier shot will always give more penetration than smaller.

Second factor may involve a lack of experience with killing a snake. I've killed a great many, and a lot of those were dispatched with a shovel or hoe. Cut the head of shortly behind where it is attached. I have never killed a snake that did not continue to move around, sometimes quite a lot, for some time after it's head was cut off. And I have touched the head with the shovel or hoe after it had been cut off, sometimes several minutes after, and the mouth would still open with fangs displayed and shut against whatever touched it. It takes a while for a snake to quit moving!!!

The important bit of information here is not to handle a poisonous snake by hand after killing it!! Just don't do it!! And don't step close to it either. I've killed a rattlesnake more than once by throwing one of my dad's wrenches from the tractor tool box at the snake and had to leave the wrench there for a good while before I could recover the wrench. And failing to recover the wrench would have been more tramatic than getting bit by the snake! Which is why I started hanging a hoe on the tool bar or frame of the tractor with a couple pieces of baling wire just for the purpose of killing snakes.

Shot shells, what ever they are fired from, and especially at very close ranges, must be aimed in the same manner as you would aim if you were firing a regular cartridge load. You can miss! It is worth your time to tack up a piece of heavy cardboard on something you don't mind marking up with shot and drawing a bullseye on it and shooting at that with your shotshell loaded handgun. Start shooting no more than a yard away. See the pattern and the area that is covered by the majority of the shot. Also check to see if any or all of the shot penetrates the heavy cardboard! Then move back about a foot at a time and shoot again and see where the pattern lands in relationship to your aiim and where the pattern gets too large to land many or any of the shot on the head sized area of the snake. Put up another piece of cardboard and shoot from the distance you determine is as far away as you can get a decent shot pattern on the snake's head. Then check to see if you get full penetration through the heavy cardboard. If you don't, that's too far away to shoot at a snake and expect to kill it. You can find the maximum distance from the snake that you can expect a sure hit with your shot and adequate penetration to kill that snake. From that distance and closer, you can expect your shot shell to do the job pretty well IF you put that shot where it must go (into the head or directly behind it) to disable and kill that snake. Remember that a snake cannot likely strike and hit you if you are more than half the length of the snake away. Some snakes are long enough that I'd stand more than a yard away!

Then stay away from it unless you have something with a long handle to dig a hole and drop the snake in and cover it up!

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So long ... Ken