I've used those .22 birdshot with the crimped end. In my .22 rifle they killed snakes well at about 6' from the barrel to the snake. I also used it to kill rats. I would put the barrel right next to their head, did what I wanted killed them with little noise. If I shot them from 8 to 10 feet they ran off. Don't know if it killed them or not. The wife put them in her .22 revolver for snakes. She tried to shoot one at 10 feet, in front of a stump, the shot bounced back and hit us in the face. No damage, it did not even sting, just felt like several flies or something brushed my face. Now the .44 shotshells work a little better with #6 shot. I have killed grouse with them. But killing a spruce grouse is not hard. Just walk to within 6' of him, lean toward him, and shoot with the barrel about 3 feet from his head. Does a real good job, but leads the barrel bad.