1/2x20 or 1/2x28 thread on 308 barrel

[Hunter_Nick]

Hey lads, I know that there are lots of rifles that come out of the factory with this thread on a .308 bore, but there is a lot of noise around about muzzle swelling with the small amount of metal left after it’s cut.

Has anyone had any issues with loss of accuracy over time, that could be attributed to this?

[Friwi]

Pressure and heat build up under the threaded portion , which can be also temporarily insulated by the surrounding suppressor.( which does not help)
Some rifle barrel hold pretty well their internal bore dimensions, some not so well . The bore dimensions on certain barrels even opens up after machining.

[gundoc]

It depends upon the material of the threaded part of the suppressor; aluminum = 1/2"x20, steel = 1/2"x28. Better still is 9/16"x24 or M14x1 for a bit more meat at the muzzle. Properly cared for, the 1/2" threads should be fine, but larger diameters are preferable. No diameter will prevent muzzle damage if the rifle is fired with foreign bodies in the bore.