Powder coated cast bullets should be fine.I have an original Deerstalker and I love it. Be weary of cast bullets, it will clog that gas port. It eats jacketed bullets like a champ. Never messed with the newer Deerfields.
If it's a lever action 96/44, they're a lot of fun and obviously port fouling won't be an issue.
I sold my 44 carbine because it didn't have the "same era" look as my Super Blackhawk. I was looking at the Big Boy carbine then a very nice Winchester takedown came available here. I drug my feet and some lucky guy snapped it up. A Rossi 44 lever came up for sale cheap because the guy was frustrated trying to find ammo. It was still NIB $600.Don’t have the Ruger, do have a Henry Big Boy in 44mag. Great rifle,
Hope the OP doesn’t mind,