Even not that long ago I remember showing up to a walmart ammo counter, you'd see some other guy there waiting, and all the while you would size him up and hope he was not there to buy the 9mm or .22 LR that there were like 3 boxes left of...
For a while if you saw anyone waiting near the ammo case at Walmart you *knew* that they were hoping for .22 or 9mm....lol.
It's going to get that way again pretty soon. AR parts are already drying up a little. I'd say if you don't have a year or two's supply of ammo, it would be best to get it real soon.