Headspace Comparator Bushings
thingiverse
I didn't want to shell out $30 for the comparator bushings, so I experimented with these alternatives instead. They're "good enough" for telling when you zero in on a case and bump the shoulder. The files labeled by case name are precision-sized to match my printer's accuracy. Those marked with numbers correspond to exact measurements in inches (0.375, 0.400, and 0.420). I even included a miniature hole size guide to help you gauge your printer's horizontal expansion, so you can tweak as needed.
With this file you will be able to print Headspace Comparator Bushings 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 Headspace Comparator Bushings.