I posted a similar message. I had problems with E-lander and Stoner magazines.
The Stoners were purchased in the 15 round configuration. If I loaded more than ten rounds, the top cartridge would take a nose-dive into the feed ramp.
Oh, and don't get me started on bending the feed lips. I was fortunate to have an MPA magazine tool that took care of the feed lips.
The gentleman that answered my question told me to get the PRI magazines. I bought 4 to try them out and they were flawless. Then I got six more.
The best price I could find was at Midway USA.
https://www.midwayusa.com/product/2367576975?pid=734854If you notice the difference between the Stoner and the PRI, you will see that the PRI has a slight curve to it. I believe this, among other things, helps to prevent the top cartridge from nose-diving into the feed ramp.