Thank you! Its 3/8 and groups well to 1000. I have the same set up in 308 that I learned on. I am glad I started with the 308 but I have to admit I don't even take it out anymore. Thanks for the kind words!
Sd of 16 and es of 30 using 147 Hornady match. My velocity is only 2700 but it handles the wind better than the 140's. My 308 is 2650 with 168's in same set up but is much more difficult in the wind. Thanks for asking!