I can't imagine why anyone would convert a Siamese Mauser to 30-30 other than same reason men climb mountains... "Because they're there!"
I have several Models 54 in carbine and one in rifle configs. Also a Model 788 and a Model 40 Savage. I have no experience with the latter Savage rifles but believe there's a passel out there and prices should be relatively good!
The first thing occurring to me in conversion, as referenced above, is going from rimless to rimmed round. A PITA alone of bolt face, feed rails and magazine/follower all likely to requiring work + fussing!
Then the comparison with the models noted above as 'of factory production & out there'. Of course likely short of conversion 'fun' slamming head into walls & such consequential! Then too, the folks like me that viewing such with the nicest comment conjuring... "Isn't that err... different!" (Maybe such as a SMLE Jungle Carbine Bubba special to further convert as praiseworthy??? :))
Otherwise, Pass-Nope, almost surely far more economical just to buy a 'factory' edition. Either for 'as-is' or as an action donor for whatever config. The aside, I'd not recommend the Savage as more 'iffy' condition & parts can be problematic.
The Win 54 is the CRF gem with the distinction of having an action specifically designed for that singular round! Really! These were only factory available in the earlier Mod 54 edition & for several years late twenties-early thirties. But they were great era-quality guns. The Rem 788 is also a sweet rifle as above noted. Also with scope application possibilities without further fuss! Also the clip detachable feature as versatile.. Just don't lose it!
The 30-30 bolt rifles can be a lot of fun, but as 'project gun, my belief most all such 'projects' not worth reinventing that wheel!
Just my take!
Best!
John
