Bump
From Noveske when I asked about the chambering of mod 0 vs 1
The MOD 0 chamber has tighter dimensions in the lead and free bore. This was proven to be a very accurate chamber but it showed some signs of high pressure and popping primer with very hot NATO 5.56 ammo like MK262. The MOD 1 chamber relieved this pressure issue by making a little more room and opening up the free bore a little to accommodate a wider range of different ammo. It's still a match chamber and very accurate but a lot of people swear by the MOD 0 chamber for it's accuracy. If you find the right ammo that's not super hot, you should get great results.