Colo Elk Muzzle loader bullet

Hello,
I was curious as to what everyone uses for elk with their muzzle loaders as far as bullets,
other then using the most accurate.
I have a Bighorn and a Revolution, both are Knight. I also have an ML II, but smoke less is not allowed.
I also know Colorado does not let you use sabots, but I also thought you could not use a bullet that was more than 2x's the diameter of the same bullet ?
Are the Hornady no sabot bullets legal ?
Anyone here want to recommend a bullet for Colorado muzzle loading elk season ?
Thanks

I have used hornaday 350 gn FPBs for deer not elk but i got dead right there results. there a expandable base bullet that got good accuracy out of