Before the most recent release of the Prof. Parabellum DIY AR9, I went through and made printable guides to cut the steel parts for the upper assembly. This includes the Upper Receiver Sleeve, Bolt Carrier Tube, and the Bolt.
You can print them out, put them over each metal section and they should give you easy to mark cutting guides so you're not having to eyeball it. The bolt section has many parts to test depths and hole locations, as it should.
Hope this helps everyone.
-Boost the Signal
First generation of parts.