I am also experimenting with modifying some M&P mags and CZ mags to use while in the carbine. You should cut the notch within the front from the mag so it is going to lock in. I don't have any Glocks. I'd personally use Glock branded magazines instead of the https://rugersr45forsale00011.blogrelation.com/38233173/5-essential-elements-for-ruger-shotguns