Since almost everybody in my team got a G18c (cm.030) I wanted to tune mine optically.
The result is this picatinny rail for mounting a red dot or a reflex visor (ca. 22 mm). Even if you don't want to mount a special visor on the rail you can use the built in visor.
I created two different versions. One with a notch to make the barrel still visible and a full one which covers the notch of the pistol slide.
For mounting: Drill some tiny holes in the mounts (of course lower diameter than the screws) so you can screw the original screws easily.
Grip for G18c: https://www.thingiverse.com/thing:2501358
Made with BQ carbon black.