I too shoot the 280. Any of the loads you've listed will work on black bear. Most use standard deer loads for black bear. I'm much like you and would rather be overloaded than under loaded. The bear claw and the failsafe will penetrate the most. The failsafe is much like an X bullet and will retain 95% or better of it weight. The bear claw is also made to retain a high percentage of weight but the mushroom size will keep it from penetrating as deeply as the failsafe. The Partition is designed for the front core to mushroom and many times it will wipe away leaving the shank to drive deeply. As I stated any of the bullets you listed will work well. I haven't had the best luck getting the failsafe's to group well. I've had good luck with the partitions and haven't used the bear claws. In general the 280 is a versatile cartridge and is capable of taking elk sized game with the proper loads.