A 45-70 shoots like a rainbow, the further away a target is the higher you need to aim. For any of the animals that you listed except for the brown bear I would have to say that 150 yards would be max. For the bear I would keep it under 100 yards just for the simple fact that you don't want to make him mad.
A lot of brown and black bears have fallen to that round and I would figure that most of them have been under 100 yards.
I totally agree with you critter on the 150 yds with the 45-70. Like you mentioned they have a trajectory like a rainbow. Definetly would'nt be my 1st choice for an open area where shots could surpass 200 yds
Has enough omph to do the grizzly but I'd limit the rangs to 100yds or less. not that it won't do it farther but you shoot better at 100yds than ay 150! If you are innharms way, and if you wound a grizzly, that is where you may well be, you need to make the best most accurate shot you can!
I've spent countless hours either on my hands and knees or bent over, messing up my back, looking for blood. One such instance I remember most was a hog hunt a few years ago in Mississippi. I had never shot a hog so when I poked a hole in this guy; I was determined to find him. Wearing snake leggings, I crawled on my hands and knees through the briars and the brambles and bushes where a rabbit wouldn't go. I found a spot of blood here and there but never the pig. And lucky for me, I didn't find...