Each screw's load/shear capacity is 87#. Each shelf should hold 348# of shear load. Brackets and boards weigh about 20# and each shelf can only hold about 3-4 radios depending on the size. Radios average 20# each. I'm about 100# per shelf total weight with materials and radios. That's less than 1/3 the total screw capacity per shelf. And if you look closely in the pictures, the screw is at the top of the wall brackets to resist even more against pulling out of the wall.
Each screw has a 'pull out' strength of 100# per embeded inch. Each screw has about 1-7/8" of embedment into the 2x4 framing behind the drywall (never include drywall in calculation). Easily 150# pull out strength per screw. That's about 600# of pull out strength per 6'-3" shelf section. Even with the 7-1/4" deep shelf as leverage against the 'pull out' strength, the shelf and radios don't even get close to maximizing the pull out load. The center of the radio's weight is really only at the half way point of the shelf at about 3-1/2" from the wall.