With that statement they prove that they know NOTHING about this subject. A full fledged .50 Barrett firing armor piercing rounds won't go through a cast iron engine block. This is just a bunch of twaddle to frighten and confuse the sheeple.
Say WHAT? I guarantee I can load up some CAST 44 Magnum loads that will bust a cast engine block all to pieces. Hell,jacketed 357 Magnums were doing this in the 30's. That's one of the reasons they were developed and accepted for police use. Cast iron is so hard it's brittle.