Just in case anyone is still reading and curious how this is working out...

I just talked to Steve Dalhke, the owner of CBI. The rifling marks in the freebore are normal and due to the difference between the bore diameter and the reamer's throat diameter. Criterion Barrels are bored to 0.2643"-0.2645". Their "Match" reamer has a throat diameter of 0.2641". That difference of a few tenths of a thousandth of an inch can show up in the freebore.

Turns out that the Hornady SST is just a short-seating bullet. It's advertised as a secant ogive but I can't tell that by looking at it. The nose is relatively short and the bearing surface relatively long so it seats consistently shorter than even a 142gr SMK. Having no other bullets on hand to compare it to I had no idea that was the case.

They're going to ream the throat closer to 0.265" for me and keep the 0.160" freebore. That will give a little extra seating room for my hunting loads without messing things up for any future loading I do with VLD's.

Again, hat's off to Steve and Criterion Barrels for unbelievable customer service. Even though there's nothing wrong with my barrel they're going way above and beyond to make me happy.