Magnum
thingiverse
This part comes straight from the 2017 game - you'll likely have to put in some serious elbow grease with sandpaper and a finisher. For the internal workings, get your hands on two springs originally meant for ballpoint pens.
Download Model from thingiverse
With this file you will be able to print Magnum 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 Magnum.