I honestly understand your passion for perfection but your approach seems a bit like the saying " throwing the baby out with the bath water"
Thread files work perfectly fine for small clean up jobs like this.
And ince there is no damage to the the crown at the bore line were it matters it's kind of trivial at best considering a suppressor or muzzle brake will shoulder out at the rear of the thread against the step on the barrel.
Yes, being a professional machinist for 35 yrs, in nuclear, defense, areospace, and computer robotics, perfection is the name of the game.
I have a thread file, still in the package.
It was never used on a single part sold to world class customers, and never used in any rifle build.
You don't do that period.
Oh I tried it, once for it's intended purpose on a non important project, and abandoned it before long, and just cut the thread.
The real world...."I'm so particular."
You have what would be a scrap part, in this barrel, subject to quarantine in a locked cage, along with attached paperwork describing the problem, sign off on by the inspection department, and who is responsible, until disposal, of said part.
Not following these instructions one is subject for immediate discipline and dismissal. Falsifying the quality or feature of any part also subjects one to a 10yr prison sentence. Nuclear and DOD are super strict, one guy served 6 yrs in prison, for his efforts.
Try to send this barrel out to a customer would ruin the reputation of the company, and require immediate action, or loss of contracts forever.
I realize that parting off the damage threads, turning, and re threading this barrel is a very simple job for me, but its the correct way, easy to save, even if under legal length, could be dealt with.
But, since you do not possess the machine tools or skills, one can sub par things to gather and hope for the best.
If the barrel has some round count on it what's the problem with just replacing it. I replace worn barrels from shooting quite often...replacing barrels is part of shooting.
So IMO, I'm not throwing the baby out with the bath water.
The barrel is a replaceable consumable, when damaged it's easily replaced, if one can not properly repair it.
It looks like crap and no self respecting gunsmith or machinist would allow a part to look like that, plus if one can afford a suppressor, he can easily afford a new barrel, but a new barrel capable of accuracy, and a quality fit for his suppressor..win, win....
That's what I'd do if I were in his shoes...simple...and give ya an excuse to have a new barrel...I like new barrels.
But file away if ya want to....it ain't mine.
Never did say how the barrel came into its damaged condition.