Or you could have one of the custom long range muzzle loaders done on a rem type action and switch barrel muzz and rifle. Mine was a 6.5-284 and I had a second barrel done in 45 cal muzz.
Contact IAhunter- Hollis Weber on here(don't think he is one much) or on facebook center punch USA https://www.facebook.com/Center-Punch-USA-LLC-272248350078595/