BLAME VISTA OUTDOOR!!!
I have been blaming Vista Outdoor, the parent company that owns and runs three of the four domestic primer manufacturers: CCI, Remington, and Federal, (amongst other shooting related brands).
They have been complicit in the on/off ammo and other shooting related shortages for probably five years. They took a lot of heat from customers over the dearth of common caliber ammo a year or more back.
But, what is really note worthy is their stock value. What an awful and risky investment! Roller coaster prices from over $50/share to a low of just above $10/share. When things are bad for gun owners, they're great for Vista stock holders, and vice versa. But from mid January to mid July of this year the stock fell by half from just over $51 to about $26, a near 50% loss! If they're going to try to keep their stock holders happy while trying to sell "bargain" priced 9mm ammo, then they're going to have to make up the difference by screwing over customers on things like primers. It's a stupid practice, in my opinion, because reloaders are the "long term" part of the shooting/outdoor market. Mess with your loyal long term customers and you're asking for fiscal volatility.
Anyhow, that's just my theory watching the Vista Board of Directors "clown show" of the past 4 or 5 years....