I’m a casual shooter, but my FiL reloads, to the tune of several thousand a year. 2 years back I was trying to get him primers and Bullseye powder as part of his Xmas present (per his request). It was out of stock through BassPro, and backordered. And pushed back. And again, and then cancelled by Basspro as they said they could not give a date when it would be filled.
Reloading supplies are in just as short supply as ‘finished’ ammunition. And heck yes, a LOT of the demand for finished ammunition driven by hoarders, especially certain right wing nuts, but a lot of the demand for both weapons and ammunition come from first time gun buyers, often non-traditional (ie female, PoC, or both) that have surged dramatically after legitimate distrust in policing became widespread. I brought that up in a prior thread -
I will agree that reloading supplies are almost certainly hoarder based - you aren’t going to be snatching this up unless you already have the equipment. Second, and a telling point, for a while you couldn’t get much if any used or new brass - people were reloading and reselling at the aforementioned 200+% over new ammo.
But the OP specifically asked
The retailers are 10-20% more. The manufacturers costs may also be higher from costs and labor standpoint, that would probably factor into the percentages above. But the high costs seen, especially online? Price gouging and scalpers. When you see someone selling WWB (Winchester White Box) of 50 rounds of 9mm Luger for $50, the answer is evident.