Capacity should always be a priority in selection of a handgun. While I love my G30SF's 10 round standard mags, more is better, right? Upon learning that G21 13 round mags would work in my G30SF, I purchased a couple. They fit fine but look a bit awkward with all that mag stick out and create an uneven grip position. I found that A&G provides a solution with their grip extenders designed just for this application (purchased from Cactus Tactical). In the photos that follow, you will see my standard setup and grip (which include Pearce +0 PG-30 baseplates) and the conversion to a G21 mag with A&G extender.
indythompson's Photostream
indythompson's Photostream