Made some progress on the muzzle bushing. Two parts to fitting this, the OD has to match the counter-bore size(15/32") and the ID has to match the barrel OD(.3435") or the original muzzle ID(.349"). Full disclosure, I am teaching myself machining as I go along on this project, I'm open to any machining feedback from those with more experience. So I ordered a .3480" reamer for the ID of the bushing. Somehow I ended up a little loose at .350" so I'm going to step down to a smaller reamer as I'd like this to be tighter than the factory fit.

Here is the first try on some brass rod for the bushing:



One of the issues with an "all in one" machine like I currently have is the effort to change over from lathe to mill. So I didn't have to remove the lathe tool post and install the mill vise I just used the counter bore on a piece of aluminum rod.



The fit of the bushing OD to the rod ID is also a little loose relative to what I expect. This is my issue as I got impatient, and of course took just a hair too much off. All good though to check my process, and get familiar with the tooling. Next round will be more focused, and more patient. In the interim I turned a taper on the EWK adapter to center the barrel in the muzzle bore. I'm going to finish building the gun as a mock up, shoot it, and see how it is from an accuracy perspective.

here is the bushing to counter bore fit: