I own a bunch of lever action rifle's. They are my favorite rifle's to hunt with. The 44 magnum is definitely enough medicine for any of the game you mentioned, out to 100 yards. My personal opinion is that the 44 is good to 200 yards in the hands of a person who knows how to use it. If you are only going to have one rifle, then I would recommend the 44 magnum, and that is coming from a guy whose favorite rifle is a Winchester 1886 in 45-70. I recommend the 44 for several reasons. 1. Light recoil. 2. Lots of factory ammo available. 3. You can shoot it alot with inexpensive ammo for practice-there is no inexpensive 45-70 ammo.
I would not recommend the 300 grain ammo for the Marlin 1894 in 44 magnum. I have seen several rifles that have a problem with the longer 300 grainer's.
If you reload and cast your own bullets then I would go with the 45-70, if not then go with the 44.
Here is a picture of my 1894. You definitely want to get the peep sight. No need for a scope. Tom.
