I've taken many black bears with my 45-70 Marlin. Virtually every bullet I used did the job but my favorite is the Speer 400gr JFP bullet. The bullet is fairly soft and expands easily. Penetration is more than sufficient. I have yet to catch one in a bear. I typically load them to 1,700 ft/sec
I did catch one in a 350lb boar pig. It expanded to 90cal and was fully intact after blasting through both shields and lodging in the skin on the off side.
For a lighter recoiling load I'll use a Barnes 300 XFP at 2,000 ft/sec. Accuracy and penetration are good.
I am going out with Hornady 350 FP loaded with R7 46.5. Which is Lymans max load, which is less than Hornady's max load of 49.8. Both manuals say 1900 for their load.
Last year I shot a buck at angle with 44g. Rear ribs to front shoulder. Dropped him, but he tried to get up so I shot again. Not sure if he would have. Found both shots under hide. Which bothered me. Both expanded very nice.
First time making an angle shots, so I can't compare.
I was thinking a hard cast 405 or so, but didn't get to it.
I shot the Cast Performance 440gr WFNGC bullet at 1600fps from my 10" BFR revolver. Never shot a bear with it but it would penetrate like a freight train through everything I shot with it so I wouldn't hesitate to shoot a bear with that bullet.
My load was a max charge for a Ruger #1 but I wouldn't have shot it in a Marlin 1895. The BFRs are a lot stronger than one of the Marlin lever guns. You'd probably be better off working up different loads in each of the guns.
Could cast your own. I had very good results with wheel weight lead and adding 2% lead free solder for tin. Makes great hunting rounds with a elemer Keith style bullet. My testing was a 44 mag but with perfect mushroom and 95% weight retention I was happy. The Hornady flex tips worked well also