I’m guessing amateur fireworks are quite illegal here in Indiana. Now, I have shot a 2-liter bottle of soda before with spectacular results, but I am thinking it would be less than dynamic with a watermelon. What I am really going for here is some sort of mass destruction of the melon. Any kinds of suggestions are welcomed.
When I lived in Northern Kentucky, it was legal for us to by fireworks in Indiana, as long as we didn’t set them off there. So we set them off in Ky., where they’re completely illegal.
Get a small plastic bottle with a screw-on lid (like a pop bottle). Add a little water, throw the dry ice in and secure the lid. Insert bottle into fruit (carve out a hole beforehand).
The dry-ice-in-bottle method makes really nice explosions.
A hollowpoint from almost any decent sized firearm will do it. Something like a .308 or .30-06 with good varmint ammo should prove spectacular. Or at least a medium handgun cartridge.