Originally Posted by
rccardr
The crown race will actually seat in the ridged area. Measure that, got to be either 26.4 or 27.0, more or less.
OK.
And edit: I went back to double check measurements and I guess I didn't have the calipers pressed against the crown like I thought I did in the last picture. I'm getting 26.1-26.3 at various points around the ridged area. So, considering the tool I'm using is pretty cheap, 26.4 sounds reasonable.