I am not so sure I would call the Knight Bighorn a pivotting hammer unless you made some modifications to the rifle. Don't they work like the Wolverine with a hammer/striker pushed by the hammer spring?

Yoter I do not not have the knowledge to make the judgements of what is legal in Idaho for you. You might want to look further into that Bighorn being legal for their Muzzleloader season.

If the powerbelt does not work but is legal, try some 300 grain Saber Tooth Conicals made by Harvester. They shoot good out of my Disc and my Wolverine.

Powder for that rifle in my opinion would be Triple Se7en 2f or 3f, what ever you can get. It should work good. I'd start them conicals at about 80 grains and see what happens.

Recommended brand of percussion cap is the Dynamite Noble RWS 1075 #11 or the CCI MAGNUM #11. Be sure and do not get the standard CCI. Make sure it says MAGNUMon the tin.

When sighting in, swab between shots if you feel any obstruction or hard loading in the barrel. Swab with alcohol and car windshield washer fluid. Then be sure to dry patch the barrel before loading. If you have any doubts of the barrel condition, pop a cap through the nipple before loading to clear and dry things out in there.

Good luck with your rifle.

I have a bunch (bought an entire case of them to be exact)of 385 grain Buffalo Bullet conicals that would also be legal. I was shooting them today with pretty good accuracy. Actually they got better when I kicked the powder charge way up. I was shooting them with 70 grains of Triple Se7en 3f and just for kicks (and I do mean that literally) I jumped the charge to 110 grains of Pyrodex P. They actually shot a tighter group, recoil was not all that bad, and I sure would not have wanted to be on the other end of that thing.