I wrote Primary Arms about the heat and the guy that responded stated that is where he runs his red dot and shoots it at times where his AK gets really hot and has never had any issues. He also stated if I do have any issues that Primary Arms will take care of me if the red dot would malfunction due to the heat.
So does anyone now a good rail for the Mossy 500 that I have, the receiver is drilled and tapped, thinking about running that red dot off my shotgun instead of my AK, or getting another for my shotgun.