Blank cartridge devices for attachment over a muzzle flash suppressor and methods of operating the same are disclosed. A disclosed example includes a muzzle flash suppressor mounted on a barrel that includes a muzzle, a longitudinal bore including internal threading, an inner cone in communication with the longitudinal bore, and a lateral opening located in a side of the muzzle flash suppressor between the inner cone and the muzzle of the muzzle flash suppressor. A disclosed example further includes a blank cartridge device that includes a tube, a cover and a stop block. The tube is sized to penetrate the longitudinal bore of the muzzle flash suppressor, and the tube has external threading to threadingly engage the internal threading in the longitudinal bore of the muzzle flash suppressor. The tube also includes an outer cone to form a seal with the inner cone of the muzzle flash suppressor. The tube further defines a core bore that is in communication with the bore of the barrel. The core bore is blocked by a constriction that defines an injector bore to provide communication between the core bore and a forward portion of the core bore. The core bore is in communication with at least one radial hole. The cover radially circumvents the lateral openings of the muzzle flash suppressor. Also, the stop block receives the tube, and the stop block includes a blind hole in communication with the core bore when the stop block receives the tube and the blank cartridge device is mounted on the muzzle flash suppressor.