I do a mess of these things. Likely, more than anyone and I have the instrumentation/machinery to see a before/after.
From what I've seen, a typical RR prefix S/N M700 lives within about a .006" window for true position and axial concentricity. The biggest fluxuation I see is the bore size differential between the front ring by the feed ramp and the rear bridge. I use a single stroke diamond hone from Sunnen fitted to a Sunnen MBB1290 honing machine. You can tell a "tight one" from a "loose one" instantly based on the tool pressure.
When you consider that they make the action in less than 15 minutes and the price point they are offered at, it's a bargain imo. FWIW, I know for a fact that Illion just had a $2.5million upgrade in machinery. The receivers I get now (OEM direct) are nicer than they've ever been.
FYI: For the 1st time in the 57 year history of this product, Remington now offers them out of the box, fully tuned up, direct as an "action only" from the Custom Shop. Their shop is literally about 200 yards from where I'm typing this and its run by a guy I've known for over 15 years. Remington has woken to the fact that the game has changed.
Hope this helps.
C.