About 35 years ago, we had a problem with birds getting into our machine shed. Metal pole barn. One shot with a BB rifle convinced my dad to look for another option...those steel BBs really ricocheted. He settled on .22 birdshot from a rifle, forget whether it was crimped or plastic cup.. Shoot a bird at about 20-25 feet, they'd fly off, but would die when they landed...after about 15 seconds. We eventually found where they were getting in and solved the problem. About 10 years later a friend and I decided to have a little sport with mice in an old granary...it was loaded with them. We found that we got sure kills with CCI plastic cup birdshot out of .22 pistols at about 10-12 feet, wounded them at 15 ft plus. Lots of dust and the patterns told us why....pretty thin past 15 feet. Maybe a smoothbore would improve performance, but not sure how much.
