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!
As a Taxidermist I look at hundreds of Whitetail Bucks every year. I know that I have seen many different ways people judge the size of racks on live deer. I think for the most part they all are pretty close. I'm going to give you some measurements that I have noticed being right on in just about every deer. We have used it in the last couple years and have only been off by about 5-6 inches. We do study the deer while bowhunting so we get a little more time to look at them....