What I'm saying is that no one is going to build a lower in this manner for a firearm chambered in 7.62 and do anything useful/important with it. Maybe the cartridge size here is a distraction, idk, but this isn't a specification that I would consider common and/or useful for 3D printing a firearm. Even if your nominal intent is just to "finish" a gun with parts you have laying around, it's not going to be something that's consistently reliable.