Doing a research on Muzzleloaders in the BATF I ran across something interesting that I didn't know,

Q. Is the Savage model 10ML rifle which has the characteristics of both a modern firearm and a muzzleloader regulated under the Gun Control Act?
A. ATF has classified the Savage model 10ML as a rifle that would fall under the purview of the Gun Control Act. For additional information about the classification of this firearm or any other firearm, you should contact the Firearms Technology Branch at (202) 927-7910.