[T. O'Heir]

Isn't going to be any damage storing with the barrel off. Mind you, the term 'long barrel' is relative. I believe the longest factory barrel is 30".
And the only stupid question is the one not asked.
Uncooked rice will absorb a lot more moisture than cooked rice, but you really need a 25 watt light bulb to heat the cabinet just enough to stop condensation. Assuming the water is caused by that. Moving the cabinet to some place that's dry would be best.