My Wally World has a ONE-BOX limit, usually 50- or 100-rounds.
One box? Really? That stinks. We have 2 Wally World stores in my town. The rimfire ammo (which they never have when I go there) is limited to 3 boxes per person/per day but with everything else, you can get as much as you want.
I also buy into the notion that the government and military, which get priority in shipments, are getting most of the rimfire, leaving little left for civilian use.
Keep in mind this was over 25 years ago but the only time I can remember ever using anything rimfire, was when the military was trying to save money by making us qualify with 22LR conversions on our M16's. That went over like a lead balloon and scores dropped drastically. A 22LR is actually 5.45 not 5.56 so accuracy went right out of the window. That and they would jam every other round. It took a whole year worth of marksman qualifications going down the tubes before they figured it out and switched us back to 5.56. After that, most of us started firing expert again.