Yes, my concern was about the increased susceptibility to galling. I am definitely no expert in this area but, as I understand it, the best way to reduce the likelihood of galling is to make the bolt lugs and receiver lugs of different hardness. Chromoly steel is easier to harden than stainless so many manufacturers make their bolts from chromoly steel.What concern? Galling? You think Tikka haven't thought about that with the number of actions that are out there? I've also never heard of an action and bolt seizing up. Also why would you be running a gun completely unlubed? What about all of the other actions that are made out of stainless? Not to mention the stainless barrels threaded into stainless actions.
Action manufacturers who combine a stainless steel receiver body with and chromoly steel bolt include Defiance, Stiller, Impact Precision, Terminus and Big Horn. Even Remington welds a chromoly steel bolt head onto a stainless bolt body for their stainless actions. I figured there must be a good reason why all these manufacturers do this.
Maybe Tikka has some other way of dealing with the issue. Maybe the majority of their rifles are sold to hunters and don't get cycled frequently so Tikka has decided that corrosion resistance is more important than resistance to galling. I don't know.
A few years ago I asked on a several Tikka related forums how Tikka deals with this issue and did not get any responses. I did read a few comments from people saying that they found the chromoly actions operated more smoothly than the stainless versions.
In the end, I was not able to find answers to the questions I had in my mind so I just went with the blued steel options.
As I said, I'm definitely not an expert in this area and am happy to hear actual explanations as to why this is not an issue with Tikka rifles.