What is wrong with the .45-70? It will kill animals just as dead as the .450 marlin will, and probably a little cheaper at that. The brass and reloading supplies for the .45-70 are readily available and can be found almost anywhere, that is a plus for sure. Are the gains from the .450 over the .45-70 really worth the extra hassle and price? A hot loaded .45-70 will come close, if not match .450 performance....To me it doesn't make any sense to get a .450 over the .45-70. The gains are minimal. Brass availability might be an issue with the .450 down the road.
Really nothing is wrong with a 45/70 in the right platform.
That said the 450M is everything a hot 45/70 wants to be in every 450M rifle.
It is a cool round which is not to say a 45/70 is not
