What is an air rifle?
The modern air rifle is a high technology weapon or tool. When you pull the trigger, a blast of air slams into the skirt of the pellet (see "Ammunition" page) in the breech. This first blast expands the skirt outwards, making the pellet grip the rifling of the barrel, so that pressure builds even further before the rest of the air blast send the pellet on its way.
Pistols are basically the same, but smaller. Pistols are limited by law to 6ft/lbs power unless you have a FAC. This makes them too ineficient for any type of hunting. Even with air rifles (12ft/lbs) the margin for error is very small- hunters cannot be too careful.