The Range at the Forestry has been closed indefinately. Best bet is to go to Southern Indiana Rifle/Pistol Club. Longer yardage to let the big guns stretch their legs.
You can also buy a rifle from the CMP and have it shipped to your residence as well. It's better to go there a pick your personally, but they can ship it to you if you don't want to take the trip. You DON'T need and FFL for it either.
^That is important. Do not put a .50 ball into a .45 barrel. It'll get stuck! Also if it is older, it may have rust and/or have a weak breech that is unable to hold a large charge of powder.
If you are using a 'old-fashioned' muzzleloader that is NOT an inline and uses a side hammer(flintlock...