Didn't read through all 59 pages, so I don't know if this was mentioned by anyone. Don't pick up barrels if you've got unlimited ammo turned on. You can't switch weapons if you do. I've forgotten twice now to see if shutting it off allows you to switch back to bow/sword. Kind of amusing throwing so many barrels if fills a square up, but your bot companions are too stupid to shoot them.
Yes, switch off unlimited ammo before picking up barrels. After you are finished with the barrels, you can switch it back on - it works super well if you do it this way.