By Vassia Barba A hero who tackled a gunman who pointed his weapon at a pastor said he “had to do something.” The terrifying incident saw an armed man approach the front of Jesus’ Dwelling Place Church in North Braddock, Pennsylvania, and aim a gun at the pastor during his Sunday sermon. He pulled the trigger, but the gun didn’t fire. Deacon Clarence McCallister, who was operating a camera that recorded the entire ordeal on video, sprang into action, tackling the gunman before he had a chance to take another shot. Mr McCallister described the dramatic moments when he saw a gun pop up, aimed at…