I'm also experimenting with modifying some M&P mags and CZ mags to implement in the carbine. You have to Slice the notch from the front in the mag so it is going to lock in. I do not have any Glocks. I might use Glock branded magazines and not the https://rugershotguns78888.blog-kids.com/32335175/facts-about-ruger-p89-for-sale-revealed