Tough to shoot birds with them as their pattern tends to suck after being shot out a rifled barrel.
Good to 20 feet for most varmints, squirrels, rats, snakes etc.
I did know one guy who reamed an old single shot bolt .22 out into a smoothbore just for those. Shot pretty fair patterns out to 40 feet or so, but the small pellets lose velocity fast.
They don't cycle real well through autoloaders, but work pretty slick in a revolver or bolt.