KAK Industry 5.56 barrel. 12.5" Midlength gas (this is rare for a 12.5" - most are Carbine Gas). 0.935" gas port (#42 drill bit). The dwell time on this combination is 2.875" with a 0.750" gas block journal.
We'll see how this works out. I think the diameter is a little small, for the dwell time, but it'll put my math to the test, if it does/doesn't shoot. If it does - that's weird for my gas port math. We'll see. It might need to go up, from what I know...