Hello! I am brand new here but not new to guns in general. Given the thorny continually changing scenes of laws and restrictions out there I wanted to check myself real quick before going down the build route. My father and myself want to do this activity together as a sort of father/son project. We figure we can both learn and both grow from sharing the experience. Now initially I was going to take us down the jig + drill press route, but decided that I couldn't resist having a new toy (for other projects outside of gun building as well). So, I am the proud owner of a cnc machine of particular notoriety when it comes to finishing 80% AR-15 receivers. My plan, since I know how to program it/drive it is to use it for my other hobbies as well (robotics, brewing, automotive) My question is around the shared use of the cnc machine between my father and myself for finishing the AR-15 receivers. Given this is personal only, and not a business (or being done at a business but in my garage) do I have to worry about the tool sharing restrictions the ATF introduced around CNCs and tools? To be safe should I finish my AR receiver, sell the CNC to my father with a bill of sale, let him finish, and then I buy with back again, with a bill of sale? Additionally, I have double checked my local city/county ordinances and there is nothing restricting me from building the ARs but I am worried about this state law: http://www.oregonlaws.org/ors/166.450 How would LEO or other entity determine if the firearm I poses when at the range or hunting for example know I built the AR legally instead of have removed the serials and recoated?