As mentioned in earlier posts.....The .333Jeffery is a specialized cartridge. Very effective for even the bigger ones if the hunter can choose time & place. I wouldn`t mind hunt a buffalo with such caliber ofcouse backed up with a heavy double.
If one should make a shortcut to ".333Jeffery" a .300grain .338cal bullet to a downsized 9,3x64 could be an option. However if one really wants the real thing there is only one way with no shortcuts. It is rewarding to own, shoot and use the real original caliber. I believe(of what I know) we are 3-4 people here in Europe who activly uses this caliber.