People hunt hogs with .17 hmr. Doesn't mean it is a good idea, however. rgilbert suggested inside 30 yards. That might be a very good parameter you should pay attention to
Oh, sure, depending on the distance and watching the hog's behavior, that it can be done. I found this video. Something has this hog's interest. I like to shoot them in the head head eating or when doing security checks (head up, still, smelling air and listening), but that isn't for a shot as precise as "in the ear" should be (but usually isn't for most folks). Check out this guy.
The problem with "in the ear" is that it is rather vague. Here is a double, "in the ear" shot as well as a head shot. This hog should be dead three times. It was with a .308 hollowpoint. It was well less than 100 yards and was not effective. This hog had to be dropped while running and then finally a coup de grace shot was administered once downed.
For an underpowered round like the .22 mag at distance, "in the ear" is probably not a very good idea in terms of aim spots. The ear is actually located at the back of the skull and located at the only part of the skull that tends to be thick, the back of the skull where all the neck muscles attach. If a bullet is going to have penetration issues, it will be there.
You don't care if the shot goes "in the ear," what you want is "in the brain."
A better spot on a hog's head presenting a lateral view would be not in the ear, but between the ear and the eye. There is less bone to deal with and you have more room for error with the shot. If you can put it in the ear, then you can put it between the ear and the eye and get better penetration.
As for using hollowpoint ammo on .22 magnum, a small, lightweight bullets, I am not sure I would bother. The issue you are concerned with most is lack of penetration to the brain, not bleeding out. If you can get a bullet in the brain, your hog should go down. Remember that while most of a hog's skull is not composed of thick, heavy bone, it is composed of two layers of bone (inner and outer "table," combined, not much thicker than a deer or human, depending on location) that are separated by a gapped layer of almost nothing up to about a half inch that is marrow space, before you get to the brain. Between the eye and ear, it is generally pretty thin.
So the long and short is that you can use a .22 mag but isn't the best choice by far. You can shoot "in the ear" with it, but a better spot would be right in front of the base of the ear, between the ear and eye which would give you more room for error and less chance of hitting heavy bone.
