That would be an illegal firearm, without special paperwork, here.
A SBR, I believe.
Over here it is illegal to make an existing firearm shorter beyond a minimum length, but it is not illegal to make a firearm longer, so those Glock stocks and carbine conversions where you sort of bolt your G17 into a picatinny'ed frame are all OK to own.
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Doubt: ...it's the only thing I'm sure of...
-Marsupials: Nature's idea of Concealed-Carry-