Part of the issue is lead. The US closed its last lead smelting plant some time ago (I think during Obama's first term), a nasty carcinogenic polluting place, don't ya know...
SO US makers of all things containing lead have been getting their lead from recycle, (a bit) and from overseas suppliers. One of the big overseas suppliers was China.
With the recent disruptions in the world, and the supply chain for various raw materials, I think the bullet makers are looking at a potential shortage, temporarily, at least, and quite likely have, or will be changing how much of what they make to account for it.
And adjusting prices,