K31 & Sierra Match King 168gr problem

Hi - I'm having trouble with getting my handloads at the correct CBTO to fit in my K31. I'm using Sierra Match King HPBT 168gr projectiles using the Hornaday OAL gauge with ogive insert in my caliper. I've got already fired brass converted to a "modified" cartridge for the Hornaday tool.

Measuring the lands in the rifle I get a max CBTO of 62.87, 61.31, and 61.82mm in 3 different tries; I measured a round that I already loaded that I can't get to chamber and it was around ~53mm CBTO. What am I doing wrong here?

Thanks in advance~