Re: Stainless 17-4 bolt and 416 action
Yes dissimilar metels will gall if the heat and stress is high enough.
17-4 has a Brinell hardness of 332 and a yield strength of 145 ksi , both of which is way higher than 416ss that stands at 40 ksi and 155 Brinell.
I would think that if you had the standard 4140 bolts treated with say the NP-3 system from Robar that you would be fine but if you wanted the extra expense of the 17-4 then that should be fine also
in either case , so long as the lugs and action are true and square with one another so they mate and share the stress evenly , I believe that you would have alot bigger problems once the pressure gets high enough to gall the lugs.
I've seen a couple guns get the bolts locked closed from pressure but they were in bone stock factory guns and the pressure was way way high , probably 1.5 to 2.5 grains above flattened primers.
Like P.O. Ackly said , the weak link in the pressure chain is the case head.