Do the math... Is it possible?
That is a really far shot. How much energy is left after that distance? I'm sure there would be a hell of a big difference in the wound between 25 yards and 2,500 yards. At 25 yards, the .50 BMG should have cut him in half. At 2,500 yards, it probably just put a hole in him. The shot should have taken over 3 seconds to reach the guy. The velocity of the .50 BMG is about 3,000 feet per second. 2,500 yards is 7,500 feet. I'm not sure what speed the bullet slows down to based on wind resistance but it sure as heck isn't still moving at 3,000 feet per second. On a moving target, such as a guy on a bike, it sounds impossible. I'd say it was a lucky shot if it was truly at that distance. Ever hear about that fish I caught... it get bigger every time I tell the story. The only thing bigger is his ego I'm sure!