2.680 for a COAL using 168 SMKs touching the lands strikes me as short. The "nominal" COAL for that bullet is 2.800 (per Sierra 5th ed.). As noted, my Savage measured at 2.8052 +/- .0003 to the lands, and my best rounds so far are seated 2.791, which is believed to be about 15 thou off.

Just a guess, but did you resize the case that you're using for measurement? (Since using a StoneyPoint gauge, or your home made one, you can't actually close the bolt, we are actually referencing off the point of shoulder contact. For that reason, you do not want to resize the case (or, possibly, half neck size only), since that will push the shoulder of the case back and result in shorter measurements.)