I am also experimenting with modifying some M&P mags and CZ mags to utilize inside the carbine. You must Reduce the notch while in the front in the mag so it will lock in. I do not own any Glocks. I'd use Glock branded Publications instead of the opposite copies. https://griffinpkusi.blogpixi.com/32450597/the-2-minute-rule-for-ruger-p89-for-sale