I think:
1. The price of the raw materials of 22LR went up in general, $0.06-08 /round is the new price for the bulk or common ammo most of us shoot
2. The manufacturers were putting as much of it out as fast they could
3. The distributors were getting huge orders for ammo from the big guys and metered the amount of 22LR they could get
4. The distributors would not fulfill regualr 22LR orders to the independent LGS unless they took huge quantities of other calibers
5. Not many LGS can outlay big money and add overhead to get a few cases of 22LR when they have to take a few pallets of $1/round stuff to get what everyone who walks in their door wants
6. The big stores decided to limit purchases to X boxes /day, this gets people in the door everyday for ammo and in general increased other sales or got the buyer adding stuff to their cart to get free shipping
7. Because people couldn't walk into the LGS to get what they needed for the range trip, they bought what they could find when they could find it, whether they needed it or not, that helped sustain the inflated market price
8. Angle shooters recognized the panic, took the time to buy their X boxes /day retail and tried to double or triple their money at gun shows, gunbroker, armslist etc., because of panic buyers validating their efforts
9. Some folks read a book like "One Second After" and think 22LR will be the barter currency in coming post-apocalyptic world and now have 20k-50k rounds of 22LR in their basements.
10. Since the latest control ideas failed, others think ammo will be attacked and banned or taxed out of existence, so they have to get it now or they never will be able to again
11. Something ridiculous like 75% of the 22LR ammo purchased since 2012 will never be shot
