The .17 hmr's casing is the same size as a .22 magnum's and the .17 has a muzzle velocity of about 2500 feet per second. A .22 lr has a muzzle velocity of 1350 feet per second. The .17 hmr has a longer killing range with very small game, but the .17 hmr has such a small bullet wounded game can happen too easily. Also the .22 lr cost about 3 cents a shot, the .17 hmr 25 cent a shot. The .22 magnum might be a good pick over both since it has almost the same velocity as the .17 hmr, more killing power and the .22 magnum doesn't get deflected by wind as much as either of the other two. The cost for the .22 magnums are about 15 to 25 cent a shot.