It's hard for me to avoid going to wal-mart because of my hours. I work 6pm to 6am, so on my off days I usually go to wal-mart just because they're open and I can get pretty much everything there in the middle of the night. Except I don't believe they sell guns at the one by my new place. The wal-mart by my last house had guns, but they sure did dwindle over the years.
I wish Sportsman's Warehouse was open 24x7. In fact, I wish everywhere was 24x7, would make my life a lot easier.
If you're mad at your wal-mart for not selling guns, then write a letter and don't shop there until they bring them back. Do what the other poster suggested, get your gun club / friends to write letters too. Maybe start a petition. The thing is, if people aren't buying guns there I don't see why they'd carry them. I would rather buy a gun from a small shop anyway.