Assuming the box of ammunition you just bought came from a brick-and-mortar retailer and was new-manufactured ammunition from one of the major domestic major manufacturers, it passed from manufacturer to distributor to retailer.
If it's imported, you can add the importer to that chain. For smaller manufacturers or commercial reloaders, the supply chain is even more complex, because they don't make any of their own components, but have to source those from the various "majors".
A big ammo crunch, like the current one or the ones in '08 or '13, will suck the supply chain dry back past the component level.
In other words, supply of cases and primers and the like starts getting sketchy because, firstly, handloaders scarf up the existing retail supply and, secondly, the majors have to start deciding how they're going to allocate their own supplies of primers, cases, bullets, and the like.
The problem is that when it gets this bad, the bottleneck moves back past the component level to the raw materials. Nosler and CCI and Olin need the raw materials to make more bullet jackets and priming compound and suchlike.
The difference between the Panics of '08 and '13 and the current situation is that right now supply lines are...to use the technical term...all jacked up.
International shipping has been a mess. Truck drivers may have been "essential", but whether or not manufacturing workers or miners were could vary wildly from state to state or country to country.
People making bold predictions of how this is going to play out based on previous situations are talking out their ass, because the current situation is terra incognita.
I doubt any one person even has a faint global picture of the state of the industry right now. Everybody's feeling their way around an elephant: "Oh, Georgia Arms had plenty of remanufatured 5.56 in stock!" or "My local Bass Pro is sold out of 9mm!" or (my favorite) "My neighborhood FFL said..."
FWIW, here is a piece of news that affects ammo price and supply concerns at this point: "Workers at Antofagasta Plc’s Zaldivar copper mine in Chile accepted a revised wage offer, averting a strike that threatened to add to supply concerns in the metal’s top-producing nation..."
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