I once touched off a 10 gauge shotgun, and it felt like a caught a Kenworth with my right shoulder. I own and shoot high-caliber firearms, but that was something.... special.

I can't imagine how badly a 4 gauge kicks... but let this adventurous fellow demonstrate - I love how he gives his head a little shake before he lights her off : "Yeah... this is a really bad idea. Better brace for maximum pain."