Hmmm... don't ya get the same recoil? It's the initial mass X acceleration until the bullet leaves the barrel, right?

I realize that if the diffuser is moreso "angled upward" it will aid in keeping the barrel down after the bullet leaves the barrel but even an amateur marksman shouldn't have a problem when using a long gun if trained to shoot properly. And, yes, I will agree that when using large calibres it can be tricky to deter lift in ALL situations. Of course, it can be a problem when shooting handguns and many custom made handguns are "vented forward" on the top of the barrel to alleviate lift but, as stated above by a small arms expert, there is no noise suppresion for a handgun (revolver).