Years ago, I read an article about a hunter who had built a very rifle for hunting large african game. I don't remember the caliber, but it fired a one pound projectile which contained a charge of black powder. Shooting it, was said to have spun the operator around and produced a nosebleed. Apparently, it was little used, for not only was it painful to shoot, but it did not seem to be especially effective in producing clean kills. Bigger is not always better. Personally, while I like to read about (and possibly shoot), exotic firearms, I tend to prefer more practical ones.