Never heard of such nonsense. I've always stored my guns in one of 3 ways and never muzzle down.1) In a case and flat under a bed.2) In a cabinet/gun stand standing on the butt.3) Sideways on a wall hanging rack.Maybe this is why all my guns are junk and should be tossed in the burn pile.
Hogwash? Hmmm. I'll get some pictures of the oil stains on the felt pads. I estimate that your new, cheap, chinese springer will drip about a half an ounce of oil when stored muzzle down for a few nights. If you want to burn it all up dieseling (along with your piston seal) be my guest. I just break triggers.
Yeah Ed.... other than the arguments for oils seeping into the wood during long term storage, I see no benefit. However, now being on my 4th or 5th wife (lost count) I have been wrong before...
This rack is normally used to store my PB's in an upright position. But I can stick any of my springers in it muzzle down. The guns in the photo are there to demonstrate how it works. I usually use the last station on the right to store springers during the break in period. Note here, I only store new springers this way temporarily until they stop dieseling.
That was only time I was told to store barrel down.