I checked with both GemTech and my gunsmith. Both said there would be no issue threading a .308 at 1/2" despite some internet commentary. My gunsmith has done hundreds off them for muzzle breaks and suppressors. So that's what I did. Used a bushing to bring it up to 5/8" and directed threaded a Tracker on to it.
Accuracy was unchanged from stock. Sub MOA with almost anything, and I can usually count on a least one or two internet bragging size groups off the sandbags.
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Not seeing any downside to just doing a 1/2" thread job. It's not exactly untested ground.