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I think it was his goal to get a class 2 fit but unfortunately my LID wasnt in so he used his AAC silencer to get a snug fit. I believe the pitch is good but the peaks maybe to high.
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IMHO, there is no reason for a "professional" to be matching threads on anything unless specifically requested to do so. A set of thread-wires is $20, a mid-grade 0-1 mic is $50-75. For less than $100 he could have made your thread to the true specs desired (class 2 or class 3). Every single barrel threading job I do the pitch diameter is checked with mics and thread-wires. I have a guy that just emailed me last week, over a year after I threaded his barrel, expressing how perfect and smooth the thread-job is and how he is still super pleased at the job I did. He said the fit is perfect, snug, but not too snug.
I thread every job with class 3 threads unless requested otherwise.
That being said, it's going to be nearly impossible for him to match back onto those threads and take just a bit more off with the lathe. If he can do that he's a better man than I am.
My preferred solution to this problem would be to stop before you do anything. Verify the pitch diameter of your barrel using the above method I mentioned. If the pitch diameter is right then the problem is 1 of 3 things. #1, it's the major diameter of the thread, #2 Its the minor diameter (in the root) of the thread, or #3 Your suppressor/mount is out of spec. If it's the barrel that is out of spec (most likely is from what you've told us) then you need to get a split die, open it up until it spins on freely, then close it down a little at a time so that it takes off only a small bit per pass, then check the pitch diameter. You will likely not be able to get a full thread form all the way back to the shoulder using a die. To finish off those last few threads you may have to resort to a 60 degree triangle file to actually remove some material in the root until your mount will thread on all the way.