The 350gr 45-70 has been a popular deer bullet for around 100 years now. I used to shoot 450gr bullets out of mine, but 350 gave better accuracy, milder recoil, and less fouling. They were also easier on a rifle that was new in the late 19th century.
Once you get over the macho "big bullet" thing, the 45-70 is an all around great rifle to shoot with. Has the range to go from mild to off the charts - just make sure you have a gun that can take it.