The shot shells are meant to be used at a lot shorter distances than 20 feet, and the shot size used is way too small for coons, possums, etc.
I don't think anybody here was advocating shots at tough, 10-15 lb. animals at .22 ranges.

I have shot quite a few grouse at 20 feet with .44 magnum and .45 Colt shot shells while on big game hunts in Montana, Idaho and Alaska.
The shot has spread enough at that range that you are going to get a few shot in the head of the bird, all you need to kill it.

__________________
U. S. Army Veteran