I'm also experimenting with modifying some M&P mags and CZ mags to use inside the carbine. You should cut the notch while in the front on the mag so it can lock in. I don't possess any Glocks. oil on everyhting else. After i shipped mine to Ruger for maintenance https://remingtonubfik.bleepblogs.com/32638545/ruger-shotguns-things-to-know-before-you-buy