Not the Hornady soft tip ammo. They look good on paper but make large but shallow wounds on bears. I wouldn't hunt anything other than deer with a 45-70 without some modern ammo.
It would be in your best interest to figure out if you have a reloading buddy, buy dies, powder(4198, rel 7, 3031, etc) and 350-400 gr jacketed or 400-450gr flat nose hard cast bullets and a 6 pack for him to show you how to assemble them. It's worth it and you will make your investment back after about 4 or 5 boxes of ammo.