Seems when certain barrels are in stock you have about an hour to order one. I was trying to get a 20" 7+1 barrel for quite a while, by a miracle I found them in stock one day and ordered one. Went back on the site later the same day and they were out of stock again.
I cannot figure out why this seems to be a chronic condition. Occasional out of stock is one thing, but the demand for these must be high and they are constantly out of stock, and have been for several years. I wonder why they don't adjust their manufacturing schedule??
I would guess several reasons for the shortages...
A. Demand keeps changing so it's hard for companies to keep up with the ebbs and flows of the market and it would be a large waste to make more parts than you can sell at any given time.
B. There are sooooo many 500 barrels available from other sources. Used barrels, new take offs, and aftermarket barrels that Mossberg may just not bother putting a ton of effort into that part of their sales and just focus on making guns.
C. A large portion of parts they make probably don't end up for sale and are used for warranty or repair services. Repairs are always going to take priority over selling parts as accessories.
D. If they were always available people wouldn't want them so much and they couldn't charge as much lol.