Here's a link explaining how to modify mags with links to store bought ones too. "TonyTheTiger" was the person who I got the idea from. They also go into how you can modify your lower/ upper to seat out even farther if so desired. I only modified my mag and seated out to where they would feed reliably. I like it but decided I run from a standard mag for now. And seat out bullets to run from a bolt gun, I think I can get more velocity that way. And then run loads for fast follow up shots with the AR. https://www.snipershide.com/shooting/threads/long-coal-223-gas-gun.7173197/