Condensation will only occur with the water vapor that is already sealed into the PCV tube.RPB wrote:Having seen some items stored long term; I'd suggest insulation too. :)
(Experienced capped and sealed waterproof pvc tubing buried and ground didn't insulate enough to prevent condensation- next time it will all/sealed pvc and all go into an even larger PVC sealed pip but space between filled with foam insulation.... then once more- This original failure was a 15 year period time)
Condensation can occur even in vacuum packed sealed tight PVC etc in the tiniest air space/void and desiccant is good, but I'd insulate too... and more cosmolenegrease packing next time.
I would suggest purchasing an 8 lb bag of Fresh Step Crystals from Walmart. The Crystals product is 100% dessicant (silica gel). Put the rifle in the PVC tube and then fill the tube space with the Fresh Step Crystals. Do not use a different cat litter product as other products have different ingredients.
The dessicant will prevent all condensation.