They are specifically made for theatrical use and are commonly used in real firearms for dramatic effect.
Since the loud report and flash of ignition, and not the projection of a bullet, is the goal of the cartridge, it can be used in firearms with different bore sizes.
[1] 5-in-1 blanks can be used in firearms chambered for the .38-40 Winchester, .44-40 Winchester, .45 Colt, .44 Magnum, and .44 Special because, although the bores differ in diameter, the chambers are of similar shape.
The 5-in-1 blanks in use today have been redesigned and are made with plastic cases that can be used not only in .38-40 Winchester, .44-40 Winchester, and .45 Colt calibers, but also in .44 Special, .44 Magnum, and .410 bore firearms.
The black powder blanks produce not only a loud report and flash, but also a cloud of white smoke.