Yes, it is factory, made in the 80s. Barrel is 22ins. IMR4350 with Nosler 120Bt,125Pt and Sierra 140GK. H4350 with Sierra 120Pro Hunter. H4831SC with Hornady 129SP. RL19 with Hornady 129SST, Nosler 120BT. RL22 with Sierra 140GK. This rifle seems to be powder specific to which bullet it likes...
Like you I had a Mod 77 in 257 Roberts and the only thing I got to group somewhat decent was a 75gr HP. It has been the only rifle I gave up on.
Those 140gr Game Kings do wonders on deer in my 6.5x55 Mod 70.
I don't carry on like some of those people do on those shows, but I have been happy, elated, grinning but always grateful thanking God for allowing me to take his animals He provides. Have been sad when the drag out was more that I would have hoped for though:D
Either will work. Me, I'd take the Whelen. I can back up what Scotty told me about the Sierra 225gr. It's a deer killer. No doubt it would do the same for a bear.
Dan.