I was looking at a "specials" listing on a web site, went to different page to look for another item, then placed an order for some bullets that had been listed on the "specials" page.
It immediately popped up that the "special" had just sold out and none were available.
Sure enough, 2 minutes later the item was no longer listed among the specials. Just rotten timing.
I can see where with a store front a very small amount of an item received could be advertised to draw folks into the store, only to find the special sold out in hopes that they would at least buy something else while there, but (at least to me) it doesn't seem like it would work that way with a web store. Word spreads fast these days when something does come available ( I posted a 'heads up' here about 5.56 slugs I found online last week ) so it's conceiveable that a hot item like primers could sell out a fairly good amount pretty quickly, even if they had a pallet full and restricted the amount per customer.
I had back-ordered an item from Midway, and later wished I had doubled the order. A few days later I happened to get an email while sitting at the computer telling me the backorder had just been filled and would be processed for shipping. I immediately went to the web site and the item was then listed "in stock", so I immediately placed another order and got the item. The next morning it was listed as back order status again. As I said, just timing.