I carried an 1895gs for a few years in Alaska. Loved it, shot Cast bullets well, thankfully cuz it's all I packed. (Buffalo Bore 430gr w/gas check) All the Marlin big bores have Ballard rifling and should shoot cast bullets well. I could hit a saucer size plate at 100-125 yards all day with mine. I currently rely on my 1895LTD III 45-70 for company.
There is a great variety of loads for 45-70 from tame 300gr to the Holy S*** stuff from Buffalo Bore and Garrett. Stuff that matches a .458 Winmag up close..or Buffalo's 325gr Speer JHP at 2350fps (22in barell).
I'd strongly recommend the Happy Trigger kit from Wild West Guns in Anchorage, Cabelas carries them $85-90, I put mine in with little trouble along with the Ghost ring sights, Bear Proof ejector Heavy mag spring and anodized follower.
After one jam where the round got stuck half way out the mag (before the new mag spring) I took it apart and polished away the tool marks on the carrier, bad ones. I hand polished all moving surfaces and after that I had the Hot knife-Butter type action.