coal diameter differences?

[gambleone]

I'm using a sinclair .243 comparator with good success, then bought another comp from midsouth for a friend, & found the midsouth diameter to be .230, while my sinclair measures .240. I thought the purpose of the comparator was to simulate the seating of the bullet in your barrel? I checked the .22 cal & it is also 10th smaller. What am I missing here?
Thanks in advance.
Greg

 

[Mikem]

Greg, the diameter of the hole in that tool doesn't matter, just take all of your readings with the same tool, and dont compare your reading with anybody that has a different brand of tool.
It doesn't tell you the distance to the lands, its just an arbitrary measurement, to use to compare one bullet to an other of the same brand, type, weight and Batch #, when its touching the lands. Its much more accurate than measuring OAL to the meplet.