I plan on going Bear hunting for the first time this year in the adirondack mountains. The only large caliber gun i have is a 7.62x54 mosin nagant with a syn stock and a 29 in barrel. Is this round good enough to take down a black bear?
With soft point bullets yes. It is somewhere very close to a .30-06 in power. A .308 Winchester is a 7.62X51 and the .30-06 is a 7.62X63. Your rimmed cartridge may be loaded to lower pressures but it is still plenty powerful enough to kill Pigs, Bear, Deer and Elk.
Not sure the rifle but I was envisioning a Mosin Nagant when I answered his post. I know a few people who bought them because they are inexpensive and ammo is cheap.
That would work fine for bear, pick up a couple different boxes of soft point ammo (Barnaul,Prvi Partizan,Wolf, Sellier Bellot)and see which groups the best.
More than enough. The 54R is roughly the same on the receiving end as a 30-06 and if you reload you can put together the same premium rounds as you can for anything else. I've never hunted mine but it's a neat little gun. I got my brass from graff & sons.
For the price and a little work, mosins are pretty decent.