Hate to start any arguments but since this was my thread to begin with let me say it the last post had nothing to do with my conscience. I just wanted to shoot this weekend so I did what I had to do. I was tired of waiting on the incompetence of others. As for what I do on my mill I understand that I have no formal training and most of what I do is probably wrong. I have also had things go wrong before and it was always with a setup that I knew was questionable to start with but I was willing to risk it due to not really having any other option. That being said, if I had felt I could not not do the operation by hand I would have jiged it up using what little tooling I have and stuck a boring bar in the boring in the boring head, run it out to the correct radius, and it would have worked fine, right or wrong. After all a radius cut such as this is simply a portion of a hole is it not?
In essence, it is (a portion of a hole) but in reality, you can't safely employ a boring bar to cut a radius, well, you can (if it's supported on both ends, and the workpiece is properly and securely fixtured, something you can't do or most likely don't have the machinery or knowledge to do), and I don't want you to get hurt. Machinery don't have feelings or a conscience. Machines hurt and kill people when they exceed the design criteria. There are much safer and more expedient ways to do it.
Probably what you did was the best solution. If it was me, I'd have sent it back, unadulterated. Far as shooting that afternoon, I have more than one rifle or handgun so with me, it's choice. Firearms are tools to me. I need more than one wrench (firearm).