Is it any wonder that people think the law is an ass? Or maybe it isn't, after all - A barrel is a piece of pipe
From the Queensland Weapons Act, Section 50A, Possession of Unregistered Firearms.
(1) A licensee must not possess an unregistered firearm.
Maximum penalty—120 penalty units.
(2) A licensed dealer or licensed armourer does not contravene
subsection (1) if the unregistered firearm is entered in the
dealer’s or armourer’s weapons register under section 71.
(3) In this section—
firearm does not include a barrel, breechbolt or top slide of a
firearm.
unregistered firearm means a firearm for which information
is not entered in the firearms register.
Then, if you go to the last pages of the Act, the included Dictionary has this gem: -
firearm means—
(d) a major component part of a firearm;
ipso facto,
a barrel is not a major component of a firearm.
Make of that what you will.