The Trapdoor has weak extraction? How can this be when the length of the entire breach block leverages against the rim and it will throw cases out with a hefty "SNAP". I can believe that cases exposed to weather and most especially stored in leather over time (as in belt pouches which was the pratice of the day) could corrode and the the rim simply be torn off, ( there are verified accounts of this) but I would never accuse the Trapdoors extractor of being weak. The extractor is on fact one of hte reasons the Trapdoor was chosen at a time when the world of firearms was going through major evolutions and there were several good but lower powered lever actions in the trials as well as a bolt rifle which became known as it evolved over time as the Lee-Enfield SMLE. Also note that 45-70 cases of the day were of completely different manufacturing techniques and materials. The cases were more copper than brass, with ballon heads as oposed to solid rims, the cases were drawn and the rim was formed by spinning and the primer was something more akin to a shotgun primer rather than a simple cup primer in a pocket. A horrid affair by todays standards.
As well, the 30-30 was never offered as a black powder cartridge, one of it's claims to fame is that it was the first smokeless powder cartridge offered for civilian sale by a US manufactuerer, Winchester of course. The load was a 160 grain bullet over 30 grains of a smokeless powder, most likely cordite, which last saw broad usage for loading 303 British cases for Her Majesty's Army. Rumors of any other loadings are exactly that, rumors. There has never been produce any evidence that the 30-30 was ever loaded by any ammunition maker with anything but smokeless.
Chainsaw, yes it does seem that sometimes we don't always get what we want, I'm sure you know the rest....I would like to have something else intelligent to say on the matter, but since I seem to be speechless, perhaps it is best to remain so. God speed in your search for your ultimate 30-30, let us know how the search turns out.
John.