First, are you talking about shooting a .35-something Maynard, or some other rifle chambered in one of these calibers?  If the latter, just use .357 Max cases loaded to suit you and keep on shooting, but if you are becoming a true believer, read on.

John Bly of Stephens City, VA (mentioned in my Maynard article in the last SSRJ) makes replacement Maynard barrels in this caliber, at least this bore size...we haven't spoken on the different chamberings available yet as I'm still in the early planning stages of that phase of my Maynard Madness Project. He sometimes lurks on this board and has sent a contribution or two to the Journal himself, so maybe we can get him to chime in here.  FWIW, he can also provide nicely made brass adapter rings to convert modern cases to the thick head style needed for the 1873 Maynard.  8)

I've prattled on enough about this for the public portion of this thread, but if you or anyone else would like to pursue it further, especially loading data, etc, please feel free to drop me a PM through this website and I will gladly reply at greater length. 

As I stated on the "Rook Rifle" thread, I think this could make a Jim Dandy woods walking rifle.   

Froggie

Nailman, if it were me in the scenario you describe, I would find the fastest twist .357 bbl I could get, chamber it with a .357 MAX reamer, and keep on trucking!  There are a lot of bullets available off the shelf, not to mention the custom stuff, for this bore diameter.  I would try to get a bullet weighing around 200 +/- 15gr.  JMHO, but that's about where I am hoping to go with my "thick rim" Maynard I am planning.

HTH, Froggie