.22 or air rifle is perfectly fine for quick dispatch, but only with correct shot placement to the head. I've had the best success on raccoons by shooting straight down on top of the head, through the brain, which is a very easy shot to do on a trapped animal. Many of us live in cities and there is considerable danger and negligence trying to shoot something at a distance. Not to mention most cities have laws about discharge of a firearm within city limits, many include air rifles. If your round won't stay on your property, you shouldn't be shooting. Without splintering off into the four rules of gun safety any further, CCI makes a "Quiet-22" round that is subsonic. Aguilla makes a .22 that has no powder at all, just the primer. The Aguilla round will work in a pistol, but will get stuck in the barrel of most rifles. The CCI Quiet-22 is just low power enough that it will not cycle the action of a semi-auto (Ruger 10-22 for example), but won't get stuck in a longer rifle barrel. Out of a 26" barreled bolt action, this round is more quiet than a Gamo Whisper air rifle. The shorter the barrel, the louder the report.