For a rifleman situated on the sixth floor of the Texas School Book Depository Building the shots were at a slow-moving target proceeding on a downgrade in virtually a straight line with the alinement of the assassin’s rifle, at a range of 177 to 266 feet.[C4-761] An aerial photograph of Dealey Plaza shows that Elm Street runs at an angle so that the President would have been moving in an almost straight line away from the assassin’s rifle.[C4-762] (See Commission Exhibit No. 876, p. 33.) In addition, the 3° downward slope of Elm Street was of assistance in eliminating at least some of the adjustment which is ordinarily required when a marksman must raise his rifle as a target moves farther away.[C4-763] Four marksmanship experts testified before the Commission. Maj. Eugene D. Anderson, assistant head of the Marksmanship Branch of the U.S. Marine Corps, testified that the shots which struck the President in the neck and in the head were “not * * * particularly difficult.”[C4-764] Robert A. Frazier, FBI expert in firearms identification and training, said: From my own experience in shooting over the years, when you shoot at 175 feet or 260 feet, which is less than 100 yards, with a telescopic sight, you should not have any difficulty in hitting your target. * * * * * I mean it requires no training at all to shoot a weapon with a telescopic sight once you know that you must put the crosshairs on the target and that is all that is necessary.[C4-765] Ronald Simmons, chief of the U.S. Army Infantry Weapons Evaluation Branch of the Ballistics Research Laboratory, said: “Well, in order to achieve three hits, it would not be required that a man be an exceptional shot. A proficient man with this weapon, yes.”[C4-766] The effect of a four-power telescopic sight on the difficulty of these shots was considered in detail by M. Sgt. James A. Zahm, noncommissioned officer in charge of the Marksmanship Training Unit in the Weapons Training Battalion of the Marine Corps School at Quantico, Va.[C4-767] Referring to a rifle with a four-power telescope, Sergeant Zahm said: * * * this is the ideal type of weapon for moving targets * * *[C4-768] * * * * * * * * Using the scope, rapidly working a bolt and using the scope to relocate your target quickly and at the same time when you locate that target you identify it and the crosshairs are in close relationship to the point you want to shoot at, it just takes a minor move in aiming to bring the crosshairs to bear, and then it is a quick squeeze.[C4-769] * * * * *