I'm not convinced about signal strength. Sprint had two bars at my house but never worked consistently. AT&T sometimes has one bar but works. Bottom line is signal bars do not truly indicate call availability. Towers do not always relay properly.
Speaking with the clerk at Academy, he stated they are staggering the times of putting out the .22 to help stop the neckbeard vultures. Other gun forums have mentioned this practice at Walmart as well. Maybe the reason we are hearing more replies of .22 on the shelves at normal times.