About five years before I retired, we moved away from the city to a small farming community the next county over. I'm extremely fortunate that the ACE in my area sells all of the popular pistol calibers as well as .223, .308, 30.06 and a few others. They stock both factory new ammo and reloads from a small "mom and pop" facility located just down the road. Whatever they don't have on hand, they can order or the Walmart probably has it. I worked at the local Walmart for a while and know that they are very well stocked in various rifle and pistol calibers. A few years back there were a rash of smash and grab thefts of guns and ammo from the displays at other Walmart's in the Memphis area, so now they only put out a limited amount in the display cases at any time.
The owner of the local ACE also happens to be one of my former partners; owning the store is his retirement gig. The local pawn shop owner stocks the same ammo and calibers, he's also a reserve officer. Another officer next town over owns a gun shop as a second job, couple of firefighters out here are FFL's and gunsmiths, the owner of the town newspaper owns a range and is a certified instructor, he's the go-to guy to take the required classes for obtaining a state carry permit.
Most small business owners here carry, as well as most elected officials, and probably 2/3's of the population either carry regularly, hunt or both. The only real ammo shortages I've experienced (aside from .22 LR) seem to be around the different hunting seasons. As a retiree, I'm able to buy both ball and duty ammo from my former PD but it's a 90 mile round trip and I can only buy 2 boxes at a time from them, so I usually get that at LEOSA re-qual. Most of the time I use the local manufactured reloads to train with and get the rest either from one of the local businesses or buy online.