For practical humane hunting and varmint control using a .22 rifle and iron sights, 50 to 75 yards should be considered max. At four hundred yards, a .22 long rifle will not penetrate a steel bucket (but it could still put your eye out kid.) And plunging fire from one mile to a mile-and-a-half would be at least as damaging as hail and could really peeve someone off at the receiving end. Good way to create bad feelings toward shooters. Before firing a .22 rifle be sure of your backstop. It is capable, under some circumstances of causing damage further out than you might realize.
atals77 wrote: Alan123, I think 223 Hornady meant the clays were being broken at 400yds by a .22lr round and not a shotgun. This is totally possible. Mind you you would have to hold your aim way above the target at this range.