This is one of those weird things where it wasn't disallowed because it was potentially unsafe, but because it wasn't proven to be safe. You're about to shoot

This is one of those weird things where it wasn't disallowed because it was potentially unsafe, but because it wasn't proven to be safe. You're about to shoot a metal tube into the sky at a couple hundred miles per hour, we don't fuck around with what we know works until we can be sure.