Not true. The BSA offers 3 shooting sports merit badges; Archery, Rifle Shooting, and Shotgun Shooting. The Rifle Shooting merit badge can be obtained using either a standard .22 rifle, an air rifle, or a black-powder muzzle loading rifle (actually, they usually use Pyrodex). The Marksmanship MB went away when Shotgun Shooting was created, but Rifle Shooting took it's place.
Cool........Thanks for the update !
http://mercerarea-bsa.org/shooting/