Why not? He obviously didn't build it to hunt animals. Just having fun with a home made cannon.
He said he’s gonna try to shoot hogs with it.
Missed that part as I skimmed though the video. I don't see how he is going to get within range of a hog but it's his time and money.
Besides, a hog is not an animal. It's a virus that needs to be taken out by any means.