Stan;
I have a copy of Snook Williamson's book and he did a great deal of work, with George Madis looking on. It is generally conceded
that he did push his handloads a bit higher than normal.
While it might be possible to venture into .348 WCF territory with 200 gr jacketed 33 WCF handloads, it is not a wise practice for our older
1886 rifles. I just handload for accuracy and it is rewarding when hunting in the Rockies for deer and bear, or even possibly a disoriented bull elk in the rut.

Ben Lilly is credited with killing at least 3 grizzlies in Mexico, Arizona, and New Mexico with his 1886 Winchester in 33 WCF. The bear that almost got Lilly in ambush
was killed on the Blue near Hannagan Meadow in NE Arizona, above the Mogollon Rim. This occurred in about 1913 while he was hunting alone, except for his hounds.
Lilly's 33 WCF full magazine 1886 is still thought to be somewhere in New Mexico.