ORIGINAL: stalkingbear
The .450 is simply a suped up version of the 45-70 with a belt to prevent firing in older trapdoor springfields. It's for people who don't reload the 45-70 to hotter pressures. I would choose the 45-70 between the three as it's going to be around forever,has a multitude of factory loadings,and it'll get the job done.
Ditto! I have a Marlin 45/70 and use a slightly compress load(well withinsafe pressures) and a 405 gr Remington FN and have great success with. Accuracy is excellent with loads of power. Diffenently a gun youneed to hang on too before pulling the trigger though. It is in comparison to my Ruger #1 in 375 H&H as far as felt recoil.
But the factory loads are fine for what you will be hunting. My Marlin likes the 405 gr, but I have other friends that use the 300 and 350gr as well. I vote for the 45/70.
Mike