RE: 8mm mauser or 7.62X54 for black bear?
 

No, the .308 is the 7.62x51, not 7.62x54.

RE: 8mm mauser or 7.62X54 for black bear?
 

The 7.62 x54 has more poder capacity and can hold a longer heavier bullet than the 308. But I think it has a little less capacity than the 06. I think using one of the old Mossin Nagants adds a little more character. With a decent soft point heavy bullet it should have more than enough power.

RE: 8mm mauser or 7.62X54 for black bear?
 

30.06!

RE: 8mm mauser or 7.62X54 for black bear?
 

what a great excuse to buy another rifle :D any will do we hunt them a lot with 30/30 here