Discription of Events: He was tailing a car that was two in front of me and when I switched into the other lane and was driving past he got right behind me and started tailing me and when he got next to me again I honked at him trying to get him to stop being so aggressive, he flipped me off and was swearing and swerving into my lane. He was behind another car and was coming into my lane and ran me off the road. I caught up to get his license plate and he held a black gun out the window and was yelling at me saying he was going to shoot me. He looked like he was in his 60s or 70s and had white hair and a white beard and was wearing dark sunglasses and a dark hat.