Well, I tested a fully loaded mag that was in a Romy clunker by slamming the rifle nose first onto my floor/carpet. Starting from four feet, I heaved the rifle straight down. I fully expected a busted mag, but all that happened was the machine cover blew off the AK as the recoil spring slid forward. Park from the latch has been engraved into the locking tab, and the tab is in perfect shape. No cracks or crazed areas visible inside or around the locking tab. Good polymer. That's the extent of my testing, and I am satisfied that these mags are going to be immune from most if not all structural problems.