There is only one gun that does not show up in a metal detector (a ceramic Glock)
This is, as far as I know, utter claptrap.
I don't know where Bruce Willis gets his information (because this stuff is almost certainly ripped off from one of the Die Hard movies and not from any authentic source) but there is no 'ceramic Glock'.
Glock pistols have components made of polymer (perhaps Mr Willis got his 'polymer' mixed up with 'porcelain' and no-one noticed) but much of the gun is steel and would easily be detected on airport X-ray.
So yes, a 'ceramic Glock' would be
very difficult to acquire because it doesn't even exist. It's this kind of nonsense which then turns up in tabloids and gets taken as fact by the public.
