Honestly in the vulnerable old 30-30 I would suggest the 170 gr bullet. The 150s would be fine for whitetail but IMO out of the 30-30 is a tad too light for blackies, especially a big one. The 170s are a bit stouter and more than enough for deer. The doe I shot with my 30-30 this year was a handload using a Hornady Interlock 170 gr bullet and it put her down on the spot.
I'm not saying the 150s would not work for black bear but its better to have that little extra. Also IMO black bear are easier to kill than whitetails. it seems to me that whitetails have a tenacity for hanging onto life.