I would opt more for a severe increase in weight as a barrel full of oil or powder or whatever would weight SIGNIFICANTLY more than any armor piece or weapon. change the weight to somewhere between 50-75 ( If a barrel of oil only weighs 10 then I should be able to carry a lid to a sarcophogus and fling it at a Gnoll like a frisbee.... right?? ) and I think that would have an immediate change into the cheese. I wouldnt necessarily change the dmg as explosions on that caliber would be quite devastating. let's be honest, if they were to follow any form of realism the dmg should actually be increased...
and as someone has pointed out.... remove the barrel inside of barrel.... that is just no where near realistic... I hope that was merely just an oversight by the dev team.
