Yup.

It's a firearm anywhere you go.

I would think so, after all, they are firearms. The laws are different with muzzleloaders than with modern guns, but they are still firearms.

Anything is a firearm if it can hold a shot by itself, and if it launches a projectile at high velocity.

actually, a muzzle loader is not considered a firearm by federal law. You do not fill out a 4473 when you buy one. You do not need an FFL to buy, sell or manufacture one. You can buy them mail order and have them shipped to your home. A felon, prohibited from owning a firearm, can own a black powder muzzle loader. **update from Illinois State Police faq page.** -What is the definition of a firearm according to the FOID Act? "Firearm" means any device, by whatever name known, which is designed to expel a projectile or projectiles by the action of an explosion, expansion of gas or escape of gas; excluding however: (1) any pneumatic gun, spring gun, paint ball gun or B-B gun which either expels a single globular projectile not exceeding .18 inch in diameter and which has a maximum muzzle velocity of less than 700 feet per second or breakable paint balls containing washable marking colors; (2) any device used exclusively for signalling or safety and required or recommended by the United States Coast Guard or the Interstate Commerce Commission; (3) any device used exclusively for the firing of stud cartridges, explosive rivets or similar industrial ammunition; and (4) an antique firearm (other than a machine-gun) which, although designed as a weapon, the Department of State Police finds by reason of the date of its manufacture, value, design, and other characteristics is primarily a collector's item and is not likely to be used as a weapon. -Do I need a valid FOID card for a muzzleloader or blackpowder gun? Yes. In Illinois, muzzleloaders and blackpowder guns are considered firearms. -How can I legally transport a firearm on my person or in my vehicle? There is more than one way to legally transport a firearm. However, in order to be in compliance with all statutes, it is recommended all firearms be transported: Unloaded, Enclosed in a case and, By persons who have a valid FOID card. -What constitutes a legal "case" for transporting a firearm? The Criminal Code refers to "a case, firearm carrying box, shipping box, or other container." However, the Wildlife Code is more specific, defining case as "a container specifically designed for the purpose of housing a gun or bow and arrow device which completely encloses such gun or bow and arrow device by being zipped, snapped, buckled, tied, or otherwise fastened with no portion of the gun or bow and arrow device exposed." -What constitutes an unloaded muzzleloading firearm? According to the administrative rules associated with the Wildlife Code, the definition for an unloaded muzzleloading firearm is as follows: "Removal of percussion cap or removal of prime powder from frizzen pan with frizzen open and hammer all the way down or removal of prime powder from flashpan and wheel un-wound or removal of prime powder and match with match not lit shall constitute an unloaded muzzleloading firearm." (17 Ill. Admin. Code, Sec 660.30)