I just finished the hunter Safety course with my 11 year old son on Saturday, and they recommended storing with the muzzle down to prevent oil from soaking into the wood stock. I store mine muzzle up because that is how they fit into the safe best, and I feel with the stock on the bottom of the safe, there is less chance of the stocks coming into contact with each other and leaving a mark. I also do not over oil my guns to the point where there is enough oil to "run into the stock".