My gunsmith couldn't do left hand nor metric threads, but I measured, with calipers, enough meat on the barrel for 9/16x24 threads. He said the bore was far enough from concentric to the OD that he couldn't do 9/16x24, so, without first consulting me, he cut 1/2x28 and gave me an adapter to step up to 5/2x24 threads to attach a YHM QD flash hider for my Ti Phantom 30 cal can. 1/2x28 on a .311 bore seems like pretty thin barrel wall thickness at the threads. YHM does make a 30 cal QD flash hider with 1/2x28 threads, so I could ditch the thread adapter if I ran that FH. Compounding the problem is that the shoulder against which the adapter or FH will index is about .572, less than the .600 that YHM specifies for the 1/2x28 FH. Do I ask for a refund and send the barrel to ADCO to have it threaded M14x1 LH or run the 1/2x28 FH and not worry about it? I appreciate any advice you gents can offer.
UPDATE: When I threaded on the can and looked down the bore, I could see baffles on one side. A test with a tight-fitting threaded rod confirmed that I risked a baffle strike. I think the problem was that the threads weren't a class 3 fit, allowing the flash hider to cant slightly because the minuscule shoulder combined with a slightly off-center bore resulted in the shoulder supporting one side of the flash hider but not the opposite side. I took the barrel back to the gunsmith, and to his credit, he refunded my money in full.
UPDATE: When I threaded on the can and looked down the bore, I could see baffles on one side. A test with a tight-fitting threaded rod confirmed that I risked a baffle strike. I think the problem was that the threads weren't a class 3 fit, allowing the flash hider to cant slightly because the minuscule shoulder combined with a slightly off-center bore resulted in the shoulder supporting one side of the flash hider but not the opposite side. I took the barrel back to the gunsmith, and to his credit, he refunded my money in full.
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