Here's a video of a hog being killed with a Gamo airgun. Note that the range is kept short to insure a precise hit and the pellet goes into the brain--not just into the head.
https://www.youtube.com/watch?v=IUUCLc0ZHhQ
Here's a video of a hog taken with a Benjamin air rifle. Similar tactics are used. Close range and a brain shot.
https://www.youtube.com/watch?v=OUEwxg32s6Y
Clearly conventional airguns (by that I mean airguns shooting typical diabolo style pellets of .25 caliber or less and at velocities in the vicinity of 1000fps or less) are not going to do any significant tissue damage except to tissue directly contacted by the projectile. Even the lowly .22LR has about 10 times more energy than a typical conventional airgun pellet does at the muzzle. Pellet expansion is nil or minimal at best and the shock value at impact is essentially non-existant on all but the very smallest animals.
That means that except when used on very small targets (small birds or very small pests like mice) airguns will provide clean kills only when the brain is hit.
A brain shot is NOT the same thing as a head shot. The brain of an animal like a hog, for example, is very small relative to the size of the head. Here's a link that has a picture of a sectioned hog's head showing the brain in blue. The picture is graphic, so don't click on it if you don't want to see a picture of a hog's head cut in half.
http://sugarmtnfarm.com/2011/08/20/of-pig-brains-and-tea-cups/
All of this means that the typical ideas about energy and terminal performance that are generally discussed when firearms are involved are pretty much irrelevant when talking about conventional airguns. Conventional airguns don't kill with energy or with impressive terminal performance, they poke very tiny and generally fairly shallow holes. Those holes must be in precisely the correct locations to have the desired effect.
To make a clean kill, the hunter must know the anatomy of the target animal well. Extreme precision is required to make the hit once the aiming point is established. And finally, sufficient penetration is a must to get through the skull.
Airgun hunting is an extremely demanding sport, much more restrictive even than hunting with iron-sighted handguns. The hallmarks of a successful airgun hunter are the ability to make very precise shots and the discipline required to wait for the proper shot.
Trying to stretch the range, taking a shot from a bad angle or hunting animals without knowing their anatomy intimately is going to result in wounded animals that will NOT be recovered. There's virtually no chance that you'll recover a wounded animal after a blown shot. The damage done is far too minimal for the animal to be incapacitated or to bleed out in any reasonable amount of time.
The more powerful PCP airguns which shoot the equivalent of bullets at blackpowder energy levels are a different story. They can be used as blackpowder firearms (or handguns) would be used for hunting.
For those who are interested in learning more, Ron Robinson (aka the Manic Compressive) has written a couple of books that detail some of his airgun hunting experiences.
One other thing to keep in mind is that airgun hunting laws can be very illogical. In TX, for example, it is legal to hunt hogs and mountain lions with airguns since they are not game animals, but it is not legal to hunt crows, squirrels or any other game animal or game bird with an airgun of any kind.
https://www.youtube.com/watch?v=IUUCLc0ZHhQ
Here's a video of a hog taken with a Benjamin air rifle. Similar tactics are used. Close range and a brain shot.
https://www.youtube.com/watch?v=OUEwxg32s6Y
Clearly conventional airguns (by that I mean airguns shooting typical diabolo style pellets of .25 caliber or less and at velocities in the vicinity of 1000fps or less) are not going to do any significant tissue damage except to tissue directly contacted by the projectile. Even the lowly .22LR has about 10 times more energy than a typical conventional airgun pellet does at the muzzle. Pellet expansion is nil or minimal at best and the shock value at impact is essentially non-existant on all but the very smallest animals.
That means that except when used on very small targets (small birds or very small pests like mice) airguns will provide clean kills only when the brain is hit.
A brain shot is NOT the same thing as a head shot. The brain of an animal like a hog, for example, is very small relative to the size of the head. Here's a link that has a picture of a sectioned hog's head showing the brain in blue. The picture is graphic, so don't click on it if you don't want to see a picture of a hog's head cut in half.
http://sugarmtnfarm.com/2011/08/20/of-pig-brains-and-tea-cups/
All of this means that the typical ideas about energy and terminal performance that are generally discussed when firearms are involved are pretty much irrelevant when talking about conventional airguns. Conventional airguns don't kill with energy or with impressive terminal performance, they poke very tiny and generally fairly shallow holes. Those holes must be in precisely the correct locations to have the desired effect.
To make a clean kill, the hunter must know the anatomy of the target animal well. Extreme precision is required to make the hit once the aiming point is established. And finally, sufficient penetration is a must to get through the skull.
Airgun hunting is an extremely demanding sport, much more restrictive even than hunting with iron-sighted handguns. The hallmarks of a successful airgun hunter are the ability to make very precise shots and the discipline required to wait for the proper shot.
Trying to stretch the range, taking a shot from a bad angle or hunting animals without knowing their anatomy intimately is going to result in wounded animals that will NOT be recovered. There's virtually no chance that you'll recover a wounded animal after a blown shot. The damage done is far too minimal for the animal to be incapacitated or to bleed out in any reasonable amount of time.
The more powerful PCP airguns which shoot the equivalent of bullets at blackpowder energy levels are a different story. They can be used as blackpowder firearms (or handguns) would be used for hunting.
For those who are interested in learning more, Ron Robinson (aka the Manic Compressive) has written a couple of books that detail some of his airgun hunting experiences.
One other thing to keep in mind is that airgun hunting laws can be very illogical. In TX, for example, it is legal to hunt hogs and mountain lions with airguns since they are not game animals, but it is not legal to hunt crows, squirrels or any other game animal or game bird with an airgun of any kind.
They don't fly as well as round nose pellets at longer distances though.
