Originally Posted by RustyRick
Thanks for all the feed back and info.
I'm sure that we wouldn't be fortunate enough that all Brake manufacturers use the same thread size so a guy could exchange and try different breaks if he didn't like it???
US standard for 223 is 1/2x28,
bigger than 308,IE 338 = 3/4-20 or 3/4-24
but if your "gunsmith" didn't stick with the standards, then you are SOL