Hi evilwrench,

Welcome!

Cool project! I spent quite a bit of time playing with various AR projects a few years ago and found that SBRs can be legally registered just as easily as suppressors by means of an ATF form and a small fee for a tax stamp. For various reasons (I'm not a lawyer, so talk to yours!), you might want to do this via a so-called "Firearms Trust".

If you get started on that 80% 1911, please do post pics of your progress!

Ken