It still could be the 1973 toilet paper shortage syndrome.
For several weeks, people perceived (due to a joke by Johnny Carson) a shortage so bought up every bit of toilet paper as it was delivered to stores, perpetuating the perception of shortage.
It is supply and demand, people have been buying up ammo since 2008, there was a little lull in there when hope took over and they thought Obama wouldn’t be elected but that didn’t last long.
Around here the retired guys know when each place gets shipments and they are there and they buy them all.
Then you add in the government buying all that ammo and it gets pretty scarce,