OK - I'll try checking it again. Will pushing a conical into the rifling do the trick? Then measure the marks on that? What I have done so far is just measure the rifling at the muzzle.
It is a 1-28" twist according to the book that came with it. I didn't think .005 rifling was that deep. It seems much shallower than the Hawken I used to have. I remember the rifling in that seemed much deeper and clearly "cut" as I looked into the muzzle. This rifling looks shallower and more rounded than that in the Hawken.
BTW - when I was shooting yesterday, I tried some 385 gr Great Plains conicals. I could set them just barely into the muzzle with my thumb, then it required a few good smacks of my palm on the short starter to get them into the rifling. Once in, they slid the rest of the way down very easily.
As I have mentioned before,Powerbelts load with thumb pressure (shot a couple again yesterday), and slide down easily. From what I've seen, the grooves in my barrel are about what the lands on most others are.

IM jaybe