I use a 17 M2 to demonstrate the power of even a tiny bullet to new shooters. Gets their attention immediately when a container of water/soda disintegrates from the impact of that little cutie. The 17 hmr is bigger and better all around. The 17 rimfires are my go to rounds when I want to limit the possibility of pass through inside buildings,live traps, or to lessen the danger of overhead shots.