Here are a few pages that might help you get back on track:
Here is an assortment of makes and models.
AEA Airguns has introduced a .72-caliber rifle that is the most powerful production airgun available today and just might be the perfect gun for hunting feral hogs in Texas brush country.
The advantage of mid-bore air rifles for predator hunting is that, to put it simply, the small bores are too small, and the big bores are too big.