Suppressor mount thread specs

[astocks2622]

I'm building my first form 1 suppressor, and want to go to with 1.375x24 (Hub) threads. I'm finding conflicting info on the major and minor diameters. One source is showing 1.370 major and 1.335 minor, theoretical machinist is showing 1.372 major, but 1.319 minor. The major diameters are close enough, but the minors are .016 different...
Any input on which is accurate?