My supplier orders direct from Federal, since he has a manufacturer's license (FFL Class 7). He has 500,000 Federal primers on backorder right now, and I had to furnish him 10,000 out of my stash to fill an order just last week.
The problem with Federal, at least with my supplier, is that there isn't any advanced notice as to when they're shipping him primers. He'll get a call that X number of primers have been shipped, and they're COD. That's hard on a small supplier, but what he has to deal with to continue to be able to order from them.
Hope this helps.
Fred