This particular gun was an actual period gun, so it could prevent the use of the gun if it needed to be modified. But honestly, just like there wasn’t a real helicopter in films besides stock footage or military footage the production company didn’t film, because accidentally killing three actors two of whom were children being illegally treated, was enough for studios to forbid it, the people who’ve been shot accidentally on film should really make everyone unwilling to use anything but a prop that is explicitly and legally not at all a gun in any way.