Seating one upside down would have been a good idea ... I didn't think of that when I was worried about my equipment being the issue. You can't seat them at all without the ridge entering, because the ridge is the first thing in
Like I said previously, I can seat a SMK without any issues whatsoever and those are at most 0.0002" larger in diameter. I'm pretty convinced that the ridge is the contributing factor ... I have no way of knowing if the brass may be over-annealed, but it works fine with the others.
Given my success with the other bullets and with the OS bullets using the NATO brass, I don't think that there are any equipment issues here.
All I'm trying to do is give people the benefit of my troubleshooting in case they want to do the same kind of loads. I loaded up a bunch of these last night with 5.56 based brass and they hold just fine. I really am sorry if I upset people's sensitivities by bringing data to the game