Just a few observations from a former Walmart ammo stalker who bought a LOT of ammo from various Walmarts over the last 8 months or so (just got into 22 then):
1. Just because the clerk tells you they haven't seen any in X amount of time, doesn't mean they're not getting it.
2. That particular clerk may simply not be around when the ammo is rolled out.
3. The ammo is being intercepted by insiders, so if that particular clerk is not "in the loop", they know nothing about it.
4. You may have run into an insider, who is trying to throw you off the track (just go away) so his buddies can buy it.
5. Apathy - after being asked a thousand times a day, many probably have a canned response so you'll leave them alone.
I was monitoring 30 or so Walmarts - I quickly learned which ones were dependable, and which ones had folks obviously playing games with the 22.
One obvious sign I ran across - when a clerk tells you they haven't seen any in X amount of time, and you ask a few questions (inventory shows it should be in stock), and they proceed to beat you over the head...well, you've probably run into an insider.
Usually it's a grumpy old white guy - 2 particular Walmarts I used to visit (5 miles apart) often had ammo show up on the same day. Went in one 10 times, walked out with 22 ammo 10 times. 5 miles down the road, walked in 10 times, never got any ammo, was told "We haven't had any 22 ammo in ages", then went home and watched inventory go down, down, down, gone (as he was obviously selling it).
I've seen employees tell folks they were out of 22, then saw them sell it to one of their buddies who came in 5 minutes after the former shopper left).
I had one tell me "no ammo" last night, then watched her sell a buddy some 223 when there was none on the shelf.
I've had a number of employees sell me ammo from under the counter (a Walmart no-no) - some probably just put it there for convenience (won't have to keep unlocking the case), but they should at least leave a box in the glass case so folks know they have it - how many folks glance at the case, see nothing, and keep walking?
Some of the employees that sold to me from under the counter knew I was monitoring them, and sold it to me just to get me to go away.
I've also seen some of those same employees offer up a number of brands / lots in an effort to get me to bite - when I didn't, they finally brought out the Winchester M*22 I was after. I'll take 3 boxes of that Winchester M*22 (3k rounds) instead of the 3 boxes of CCI MiniMags (300 rounds) she tried to push on me to get me to go away (obviously trying to hang onto the M*22 for her buddies).
I've got all the 22 I need, but I may start helping out some youth programs at our local range, so I'll probably soon be looking for more for the kids.