Hi
I have sanded the channel after fitting a new barrel, the material removes easy.  If there is a lot of interference rough it out with care.  Once close use emery tape under the barrel, the back of the tape may be abrasive so protect the barrel surface, I used paper towel on the tape.  Work the tape in and up the channel with a sawing action. (y… Read more

Watch using the Std Tikka rings as they are 26mm diameter not 1″.
If you take the small bottom piece and place it onto the scope tube, it will move/wobble also showing a visible clearance at the sides.  Not the right fit to support the scope tube!!
The top piece conforms easily with screw tension.
Do the same on a old 26mm tube and the bottom piece… Read more

The bolt should never be tight with factory ammo as any SAAMI spec ammo will fit any SAMMI spec chamber.  That is the purpose of the SAAMI regulations.
Have the gunsmith look at the chamber and bolt, if there is any real problem get the Tikka Agent involved.
PS: keep the bolt lugs lubed always as a jammed or tight bolt will score the lugs if dry.

I just don't lap.
I centre the reticle, sit the scope in the rings (not tight) and look at a target (20m) through the scope and bore.
When I see that the scope and bore are not aligned, I lap the bottom halves only with a 25mm bar and emery tape, left or right/down until alignment is gained.
The rings are usually no longer round, so I bed the scope… Read more