Even if it will keep the suppressor attached, one concern with using minimal thread diameters is the lack of strength when ( probably not -"if") the suppressor is bumped hard, from a fall, or any other cause.
No getting away from the fact that it will take less impact to bend a 1/2" thread on a .30 caliber barrel; .264 should be a little stronger, but not enough for me.
One time I experimented with a mock up in this configuration; a surprisingly small smack was enough bend for baffle strike. Enough to cancel my plans for such an application.
9/16" is the minimum for .30 that I have found approved by any manufacturer, except Kimber, who uses a 7/16" (
Yes, Seven) thread on some of their .300 Win Magnum rifles.
The FAL, with 9/16" muzzle threads, has those threads far up into the inside of the FH, with much of the body extending back over the larger barrel diameter for support
As long as this is a thread Thread
, there is really no reason for a 1/2" thread on most .223, even ARs, except for the fact that it started out that way, and was never changed when the Military dropped the pencil barrels. The standard .750 gas block AR barrels usually have enough muzzle diameter for 5/8" threads. I use 5/8" on all my .223 applications, when possible.
That also makes it easy to use the 5/8" thread direct thread cans on all barrels.
But, a half inch thread can be, and sometimes is, used on the larger calibers. Your call, and I wish you well with it.