Download to at least 28 or maybe lower. DO NOT store loaded 30rd mags loaded full (30rds). I had a chest pouch with eight 30rd mags loaded to 30, this being my SHTF pouch, I never touched it. I used other mags for shooting. After hurrican Rita, the my hunting crew went to our cabin in the woods to check it out. I had been wearing or carrying the chest pouch since returning after the storm passed. There were some very big limbs in trees all around our camp, so we decide to try shooting some down. I unload the mag in the gun. I then reach in the pouch and grab one of these fully loaded mags. I attempt to insert the mag (closed bolt), it won't go in. I slam in into the mag well, it bounces out. I take the rifle, lay it on the arms of a chair on the porch with the mag well facing up. I slam it again, it bounces out of the mag well and out of my hand onto the ground four feet below. These mags had been in that pouch for two to three years. Imagine after five or ten years... It won't wear your springs out, but you'll play hell putting one in an AR with a closed bolt.
TS