Well while I do not have a Lyman Great Plains Hunter, the 1:32 twist should shoot conicals real well. I would GUESS that the Hornady Great Plains, the Lyman Maxiball, and even some powerbelts SHOULD shoot well. Again, this is all a guess based on how my CVA 1:32 twist barrel does. Whether this barrel will extend your range a lot, I could not say. I would not shoot my CVA past 100 yards, but then it is a carbine. I bought it as a short range tree stand rifle (and just because I did not have one of these.. ).

If you're having good luck with your current rifle and a maxiball. I think you have all the elk medicine you need. I have a real liking for the 370 grain maxiball.

I do shoot a Lyman Trade Rifle in .54 caliber with a 1:48 twist and an excellent load is 90 grains and a 405 grain powerbelt. I really suspect that load would be elk medicine. Of course for Whitetail where I hunt, shots are not that long, soI hunt with roundball. It is all that is needed for deer under 100 yards IMO.

Welcome to the forum. Nice to have you here.