You should never fire blank ammunition at a target distance less than how many feet away from you?

Firing blank ammunition at a target distance of less than 20 feet can pose serious dangers due to the force of the gas and the potential for wadding or debris being expelled from the muzzle. Blank cartridges, while not containing a projectile, generate significant muzzle energy that can cause injury when fired close to a person or structure. The 20-foot minimum distance is established to ensure safety and mitigate risks associated with gas blowback and any other materials that might exit the weapon upon firing. This distance allows for a safer training environment, ensuring that those participating in exercises can do so without undue risk of injury from the effects of blank ammunition.