I got my MGSL for my gen4 G26 and I LOVE IT!
Using Speer Lawman 124gr +P 9mm (agency issue training ammo), my groups at 15 and 25 yards have been cut almost in half.
I'm sure these results are not typical, and I considered my G26 typically accurate before installing it. But now, it's a tack driver. I was on-target as easily using my G26 at 25 yards as I was using my issued G21!
I'm thoroughly impressed! Thank you Mr. Graham!