Both Dick's near me get regular shipments of 22LR. The trick is to find out when they get there, make friends with the guys, and call ahead. I have bought 22LR every week since the beginning of the week.
Example, today, I called at 9:30 and they said, yep, got a bunch of CCI bricks. I asked them to hold two, by the time I got there at 12:30, everything had been sold. The guy said "Yours are the only ones left in the building."
So, my point is, don't just look at the shelves, chat the guys up and call often.