February 22, 2020 Update:  The highlight of this week was making, testing, and filming some experimental shotgun slugs based on the concept of the 7.92x41mm CETME cartridge: a long, aerodynamic aluminum core with a heavy copper rifling band to provide good stability.  Machining the aluminum cores individually on a manual lathe proved to be a little tedious, and that limited the number of slugs I was able to make for testing, but overall they performed pretty well.  Maybe someday I can build a CNC lathe to make production of repetitive parts like this easier.  I did make a little bit of progress on building my CNC router this week.  Anyway, this weekend I think I will upload another armor testing video, since I still have several in my upload queue.