Gotchya, so it the post thicker or thinner than the 3-15? I’m just trying to figure out how the zero stop shims would differ between the two models other than maybe the outside diameter as I’ve read the 3-9s turrets aren’t as big.HD is a splined shaft. With a single screw in the center. All the screw does is hold the cap on, twist tension is on the splines.
Classics are a smooth shaft with tension screws around the shaft, and the twist force is from screw tension.