I am also experimenting with modifying some M&P mags and CZ mags to work with during the carbine. You must Lower the notch while in the front in the mag so it can lock in. I do not possess any Glocks. I just paid $three hundred for any blue P85 https://rugerp89forsale33397.bloguetechno.com/ruger-sr45-for-sale-an-overview-67366358