2021 Ammo prices average 9% lower on most grades and calibers, excluding two exceptions, .45 Long Colt, and .410 Shotgun Slugs and Buck Shot which increased up to 50%.
Ammo prices are going through cycles of prices dropping, then rising again slightly. The driver behind this is the production cycle. When Ammo producers set up their production lines, it takes time, unproductive time, so once they get them running, they like to stay running as long as possible on one product.
They will ship quantities of this ammo, to tiered customers, possibly during shortages at say 50% - 110% of what they have averaged ordering for the past 12 months. When this particular run of ammo starts arriving to sellers, prices drop.