He can't actually block it if someone leaps in his face and fires a gun, but if he sees the person aiming and has a 4-5 seconds to adjust, he could probably block it from more than 20 feet away.
Edit: Unless the person was in his face and aiming, then he would just attempt to bash them in the face. He can't block a point blank shot, or one within about 10 feet. I also changed his tier with weapon. I also added more about the Blurring ability.