X-caliber barrels. 3-groove rifling. They had a 3-groove blank, and I chose it instead of the other rifling profiles. Barrel profile is SPR, 1:8 twist, Wylde chamber, mid-length gas, .750 gas block journal, 1/2"x28 muzzle thread, weight is 2lbs 2oz. I paid extra to have it bead blasted.
Photos show exterior, and bore scope shows the throat and a random area in the barrel to prove it's never been used, and the quality of the hand lapping.