Mr. Specter. How would the fact that the street had a 3° decline affect the difficulty of the shot.
Sergeant Zahm. It would make it easier because Oswald was in an elevated position, and therefore if the car was traveling on a level terrain, it would apparently—he would have to keep adjusting by holding up a little bit as the car traveled. But by going downgrade this just straightened out his line of sight that much better.
Mr. Specter. So that if the car had been proceeding on a level, the assassin would have had to have raised his weapon as the distance between the rifle and the car increased to allow for trajectory?
Sergeant Zahm. No; just to allow for the movement of the targets, the travel. Assume that you are aiming standing at ground level and aiming down a little at somebody walking straight away from you, and you could hold your finger and point to him and never have to move it. But when he gets to the bottom of the hill and the ground levels out, then as he continues on you have to point your finger——
Mr. Specter. Raise your finger as you are indicating with your finger now?
Sergeant Zahm. Right; you would have to raise your finger to track the target.
Mr. Specter. So that if you were aiming at a man in a moving car driving on the horizontal, as he got farther away from you, would you (a) hold your rifle at the same level, (b) lower it, or (c) raise it?
Sergeant Zahm. If you were in an elevated, a slightly elevated position, and he was driving on straight level terrain, you would have to continually track and raise your weapon as he increased his distance from you.
Mr. Specter. And if he was going down in an angle of descent, would that decrease the necessity for you to raise your rifle in tracking him?
Sergeant Zahm. Right; it would slow the movement down. There still might be a slight movement, but it wouldn't be as fast. Therefore, not affecting the aiming or possibly having to introduce a lead in your aiming, because the target is staying relatively in the same position on the line of sight.