500 is a relatively easy shot....at a stationary target, your on a bipod with a rear bag, you do not hafta swing the rifle and maintain a lead which is calculated according to the speed the intended target is traveling, while adjusting POA determined by the angle of the target with each step, the 300 RUM will not make 500 yards in less than 1/2 second so at 17.5 mph you would definitely need more than 13 feet of lead, and maintain the follow through after the shot, basicly its a 100,000 to 1 shot.
no not buying the gun and shooter are capable bit, have done a bit of shooting, it was pure luck if it did happen.
RR