Suggested by Destroyer Copperhead has some guns and different equipment at the ready but nothing that would really pose any kind of threat to Hedorah. We have to remember that this is a massive Kaiju who even overpowered Godzilla. Copperhead would be on the back foot right from the start and would not be able to make any kind of comeback. His shots would just bounce back and that would be game over for him. Hedorah wins.