My advice, get a 4x4 chunk of hard wood, and shoot at it until you find something that will penetrate.
At 10 yards and under, I assume it's a controlled situation with the animal restrained. Still, any animal injured is dangerous, especially hogs.
Consider that a standard pellet gun puts out anywhere between 6fps to 50 fps. A .22 long rifle puts out 135 to 150 FPS or there abouts. Not sure I'd trust a 22 long rifle to reliably penetrate a hogs skull, so whatever you do, be careful.