Well, I'll take a bit of a different direction here, but even with that know that I am not in any way a hater of the triple 4. Not at all.
However, much of the information I read on the forum about shooting and hunting with this fine cartridge speak of loads fired in excess of 2000fps. Some well in excess.
My first cast bullet critter was taken with a 355gr Wide Flat Nose (WFN) 45/70 bullet sent out the tube at just over 2300fps, and let me tell you I never want to see that size of a wound channel again. And this from what is basically a non - expanding bullet or one on which expansion would be minimal at worse.
Explain to me why a similar bullet fired at similar velocities from the .444 would not give similar and excessive results.
Well then, enter my next critters, more deer and a couple elk, taken with again, the 45/70, but this time with a 465gr cast WFN at the rather sedate velocity of 1650fps, that bullet and weight provide for great and long penetration, being very deadly while minimizing the meat loss of the lighter but MUCH faster bullet of similar design.
So, again not hating the triple 4 in any way, but if a person were to follow what I see to be the common trend of plus 2000fps velocities many times used with the .444, why wouldn't there be the same excess of wound channel and meat loss that was seen with the light for .45 caliber 355gr bullet in the 45/70 when similar bullet designs are used?
Recoil ------------- Well, the 465gr cast bullet in the 45/70, fired at 1650fps recoils MUCH LESS, I mean LOTS!!! less, then the 355gr at 2300 - 2500fps fired from the same rifle, so why would a heavy for caliber bullet in the .444 fired at 2000+ velocities not also be heavy in recoil.
Saying all the above to just to give a bit different perspective to the .444-45/70 question.
Although I really believe a .444 could get er done, with the 45/70, I have the advantage of much greater penetration at a lower velocity with less recoil then I might see with a .444 if loaded to the levels I typically see listed.
Could be happy both ways, but the big heavy bullet in my 45/70 has really made a believer of me.
Crusty Deary Ol'Coot