Not sure if the thread is closed but i'll throw this out too, i'm a bomb nerd so here it goes.
Everything here is open source.
That numbers are maybe a bit out, but 800m is gtg for sure man. no probs.
The way they establish danger close distances is itself a big mystery but the distances are pulled out of .1% of probable incapacitation. "Incapacitated" being 'out of the fight for up 5mins' or all the way to 'dead'. This info is all detailed in the 'JFIRES Manuel'-the Jtac's little handheld bible off everything coming out out of the sky. The conditions set for the 'DC' test is a lone dude laying a field in winter kit, head towards the tgt and the wpn impacts perpendicular to his line of body. wierd-i know.
The wieght of the bomb is only one piece of the puzzle, the type of fusing, drag, and elevation of tgt etc all come into play and not to mention there are specific versions of that wpn that are design to be Low Collateral Damage variants. The Risk Estimate Distance for a 500lb JDAM GBU38 contact is 185m, having said that you could be 60m away behind a good wall and not be messed up.. or 500m away standing up on a roof (because everyone wants to see bits go flying) on a overcast day with low cloud cover and it can put you on your ass.
just ask the JTAC... or watch what he's doing. If he's behind a wall, chances are you should be too.
Hope it helps, though i'm sure you've already won the bet.