It means that even though there is literally no difference between your definition of seeing somebody aiming a rifle and seeing somebody firing a rifle, you somehow can just tell that it’s being fired.
If you don't want to believe Brennan saw the rifle fired as he stated then don't. Works for me, but don't say he never said he saw the rifle fired, when he did in a newspaper story and a FBI Affidavit on 11/22.
As a result of having fired these carcanos, I get it there is not much to them. You can shoot these rifles one handed.