I'd say .357 would be the minimum if it's intended as the primary hunting weapon. But I'd probably not be comfortable with it. I'd go 44 mag as minimum primary hunting pistol.

You could carry the .40 as a side arm just for self protection, but it's not the type of caliber you'd expect to drop an animal with one shot. Or even several as stated above. You could kill a hog with it, but probably not a head on shot. And if it's for protection, it'll probably be a head on shot.

Go with a reliable 44 mag revolver and you won't be sorry.