Ruger (and possibly others) Thumb Saver
cults3d
I saw the Ruger Mk I/Mk II/Mk III Magazine Thumbsaver by lowside (https://www.thingiverse.com/thing:1596147) which was awesome, but it wouldn't work with my Mk 4 which has the side magazine release. So I modded Lowside's thingy in tinkercad to open it just a bit for the Mk IV magazine. It's working great for me, so why wouldn't I share?! I have found that this design also works with other pistols like the S&W victory. Try it out and report back and we'll add the models is works with here.
With this file you will be able to print Ruger (and possibly others) Thumb Saver with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Ruger (and possibly others) Thumb Saver.