I am not referring to a scenario where one cartridge has a bullet in it. I have read of a specific case where a blank cartridge was fired and yet the person still died. If no bullet was in the round, how could it kill someone?
When the chemical propellant in the charge burns, it results in a lot of expanding gas. And that has to go somewhere. In open air it just spreads out and makes noise, but if it were placed directly up against something that’s still enough to blow a hole in it.
Or picture it being the same amount of force that would push on a bullet, instead pushing on whatever else is in the way. Air wouldn’t carry energy much simply because of how it disperses, but against somebody’s head a small chunk of skull bone would essentially become the bullet.
The cartridge of a blank round still contains gunpowder and creates a similar explosion within the chamber as what would propel a bullet down the barrel. The most obvious danger is the powerful blast of gasses exiting the barrel; even without a projectile that blast is capable of causing serious and even fatal wounds at relatively short range. You would not want to be within several meters of the end of a barrel firing blanks for that reason alone.
Another major issue is that even though there may not be any bullet in the blank cartridge, anything within the barrel becomes a projectile. The range of possible barrel obstructions is limitless, but imagine for example there is a scene being filmed where an actor fires a few blank rounds then drops their pistol to the ground. The first time the scene is shot it goes flawlessly, but when the pistol was dropped to the ground a piece of gravel made its way into the barrel and got wedged so it didn’t fall out on its own. Now the second time the blanks are fired through the pistol the piece of gravel is ejected at high speed as a potentially lethal projectile.
Even the round itself can provide substances that can become projectiles. A blank often has an end which is simply the crimped together metal of the casing. Perhaps as the blank round is fired and that crimped metal is blown open it tears, and a jagged shard of the casing is thrown out the barrel. Or perhaps even just some unburned gunpowder becomes the projectile.
I know of 3 cases.
One there was a magician, he tapped the gun and the tip of his wand fell in the barrel. The blank then fired the tip from the wand that was in the barrel into him during the trick and killed him.
An actor took a gun with a blank, pointed at his head it was believed iirc that he didn’t intend to kill himself but didn’t realize it would be fatal when he pulled the trigger. In This case it was just the energy coming out of the barrel that penetrated his skull.
Then there was another case I think the crow, that one had a bullet, no charge but they forgot and left the primer I which is a smaller charge that sets off the gunpowder, but was enough to launch the bullet and kill him. So not exactly a blank.
The air and gasses from the burning gunpowder can *be* a bullet if they’re moving fast enough, like water in a water-jet cutter. They spread out and slow down *pretty* quickly once they leave the barrel, but not instantly.
Blanks contain the same amount of gun powered as a live shell, sometimes even more in order to create a more impressive bang.
The force created by this is still enough to fire a bullet, the force is focussed down the barrel.
If you were within a few meters of the barrel with it pointed at you this could injure or kill.
There’s also wadding to keep the gun powered in the shell, as there’s no bullet to keep it in place, this can also become a projectile and kill.