I'm also experimenting with modifying some M&P mags and CZ mags to implement from the carbine. You must cut the notch while in the front on the mag so it can lock in. I don't very own any Glocks. oil on everyhting else. Once i shipped mine to Ruger for https://ruger-p89-for-sale24454.imblogs.net/81916026/everything-about-ruger-p89-for-sale