I bought the bit from Brownells. Pretty thing. I guess I could grind something that would work if I had to, but this one is nice. It's .050 wide. I understand the thread width must be smaller than the width of the groove it runs in. They both can't be .050. As I cut the groove wider I'm also making the thread narrower, so it won't take much to make it work. Actually, as I understand it, thread width isn't critical in the least, but major diameter is the only thing that will center the barrel in the receiver. So, we're going to match the outside diameter of the barrel shank, to the diameter at the bottom of the thread grooves in the receiver. Since everything is going to center on the bottom of those threads cut some 90 years ago, I wonder how they were cut. Single point on a lathe, big tap, big tap with a pilot? Wonder what the tolerance was for major and minor thread diameters in 1917. I never thought about the centering aspect of barrel threads before. Very interesting. I don't have the old barrel. I do have a P14 barrel. Hence the questions about the cone angle. Thanks again for the help.
