A firearm is a weapon that launches one, or many, projectile(s) at high velocity through confined burning of a propellant.
A blank pistol, which is incapable of firing a projectile does not meet the definition of a firearm by anyone's standard.
In addition, these are not made to the same standard as firearms and often function quite differently than firearms in regard to safety features.
They are not firearms.
They are glorified cap guns.
Is that in simple enough language for you to understand????????
