I have used a .177 pellet gun and a .22 for squirrels. But in my present situation, I probably need to use a shotgun. I have found 7 1/2 shot inadequate, but #6 shot does kill squirrels.

However, I will be shooting over water where ducks frequent. I should use steel shot. Should I have to go up to #4 steel to kill squirrels dependably?