Finally...first attempt

[Ian]

You've been reading the right kind of stuff and your thinking is spot on. Fit alone won't take care of all of it if the forcing cone is really rough, I've been where you are with half a dozen revolvers and smoothing and polishing the forcing cone got me the rest of the way there every time. I've done everything from turning lead laps and brass laps with a rod inserted through the barrel to pulling the barrel and cutting a new throat with a boring bar in my lathe. Renting the right tools would be my recommendation.

I didn't know this wasn't also a gunsmithing forum, a lot of us have gotten so fed up with "dimensionally challenged" guns and reloading equipment that we've taken up buying machine tools and learning how to use them as a second hobby.

 

[Brad]

A brass lap, cut to the right angle, driven with a centered rod thru the bore can clean up a rough forcing cone. I suggest a well centered bushing in the muzzle to prevent screwing up the bore.

Ian is right, get the right tools to do it right.