Dan: And in that sense, I too can agree: if the referenced dimension is thought of as just that, a reference only. But for the true distance from the bullets ogive point-of-contact with the rifling, a dimension that is unique with each rifles chamber, it is not the true throat depth or length-to-ogive. If using the Stone Point/Hornady gauge with the ogive gauge attached, you will get a different measurement than you will with the Sinclair nut, so that would confuse the issue even more. Adding the nut width of 1" across the flats, and thinking of that as a true dimension, would add 1" to whatever the point-of-contact really is.