Quick question: does anyone know the dimension from the top of the Tikka T3x's receiver to the center of the bore? I cannot find this info anywhere online.
Looks like that'll be what I have to do, although I'm not 100% sure how to get a solid measurement other than to 'air measure' this dimension and rely on just eye-balling it to estimate when one side of the mic is in the center of the bore.
Measure the whole thing and divide by 2 or subtract .5 of the bore if action isn't round, you can also use the bolt assuming the center of the bolt is the center of the bore.
I've not taken it the action out of the stock ever (just a few weeks old - the rifle, that is), so I'm not sure if it's symmetrical about the bore axis or not. Otherwise, yeah, I could do what you're saying and easily come up with a measurement.
Open the bolt and measure from the middle of the bolt to the top of the receiver. I'm pretty sure that is all I did. There was a link posted on here awhile ago talking about measuring this if I recall. I could be wrong though.