Upgraded Case/Bullet Concentricity Gauge
The original version I built is the thumbnail for this video...
The 3D printed parts are Carbon Fiber PETG... very strong and just flexible enough not to shatter/break so easily. I kind of like the flat finish on the parts too.
The improvements are a 100% success! It took me a long time to come up with this solution using the parts I already had... cost for improvements $0.0! ( i already had the rolls of filament and the parts didn't use up much of what I have. Being the cheapskate that I am that made me happy!