My experience has been with the Model 1 sales barrels...The thread dimension at the flash sup end is 1/2 X 36 tpi. The first one I bought was a twist other than the twist advertized but shot everything but the 240SMK's really well, I've since had Model 1 exchange out that barrel for an 8 twist and it shoots very well too.
I have another Model 1 barel in 8 twist thats had 100 or so rounds through it I'd sell for $175 ( plus ship) because I've collected too many and have other projects that need funding.
