You call these project[s], which I think is very accurate for the higher power cartridges. You sound like you've seen a lot of the videos of 3D printed firearms, and from what I can tell they cluster around 9mm and 5.56. There's probably multiple reasons for that, one of which is that those round sizes are more widely available and cheaper, while another is that it is going to be easier to do than something with higher power. So to maybe simplify my point, the technical challenges and inherent safety issues on 7.62 are higher. Thus, projects they shall remain.

At this point with a 5,000 round endurance for a plastic AK receiver, I think it's fair to say the 'project' has reached maturity. Especially when this is all completed on entry level printers

5k rounds is impressive, I will concede the point if that's true. I would like to look at the design of this. Do you have a link to the CAD files, or whatever you have that explains how they deal with pressure issues.