[A.A. Cunningham]

Less than 100.

Marines are trained to shoot and hit targets at 200, 300 and 500 yards/meters from a variety of positions with iron sights.

Killing Kennedy was easy for a trained marksman. Most neophytes given about two weeks of training could have pulled it off.

[rabidralph]

Or attend an Appleseed and learn to do it in a weekend. Thanks, all, for the info.