Dogs are not people on drugs. If you know dogs as well as I do, we can talk.
Here is why I think shooting the dog with snake shot is a bad idea
The dog is acting in a manner that brings a reasonable person to believe force is necessary to stop the dog.
The first round of shake shot drives the dog away and he goes home.
Dog now has many tiny shot inside of him.
Maybe the owner does not notice, or does not understand what is wrong, or
is too cheap to take him to the vet. Dogs owner finishes the job
or leaves the dog to die a poor death.
Maybe the owner figures out what happened, takes dog to vet, cops
come talk to you about why you put snake shot into the dog.
What, exactly, do you know about dogs that makes any difference
in the above scenario?
If you know dogs well enough to keep things from going to a defensive
shooting, great!
Once it comes to using a gun to stop the dog I think snake shot is not
the cartridge to use.