6mm (.810")
1/2x28 tpi (small)
9/16x24 tpi (medium)
5/8x24 tpi (large) <--My choice
6mm (.540")
These are the ones I hate. For me, there just isn't a warm and fuzzy feeling on this one.
(1/2") = Not as much shoulder, as i would like, for the brake to seat against. And if the bore isn't centered in the barrel it makes it even worse.
(7/16") = Not a commonly offered muzzlebrake thread diameter. Also getting kinda thin between the bore and the threads.
If forced to put a brake on this one I would look for a very fine thread in 7/16", or make my own.
.277 (.660")
1/2x28 tpi getting a little on the small side.
9/16x24 tpi <--My choice
5/8x24 tpi getting too big for a good shoulder for the brake to seat against.
The TPI's that I listed are just a common choice. If the brake you want is offered in 32 tpi instead of 28, it will work fine.