Congrats on the new G27!
The magazine springs will loosen up over time. Do you run 9 rounds? Or 9+1? If you lock the slide back first before inserting the magazine, you won't have to fight that spring tension. Some of my Glocks couldn't be run in the +1 configuration until the spring loosened up a bit. I personally don't carry in that (+1) configuration, but did want to let you know that it is easier to do so after the magazine has been cycled through a few times.
Ammo by Dillon and Hornady