Originally Posted by Tyrod

Then there's the idea of "constructive intent". This originally was a fed idea. I believe it's a regulation as opposed to a law. I wouldn't be surprised if California had similar regs or laws accomplishing the same thing.

Anyway, the idea goes like this. If you own a part that would render a compliant gun non compliant, then you're guilty of owning or building a non compliant gun. This reg came into play big time during the fed AWB. It's not something the feds liked to hang their hat on. In other words, if there were bigger issues at stake like owning an unregistered machine gun or an unregistered short barreled rifle or shotgun, they would tack constructive intent on to the charges under the legal theory that if you throw enough poo at the wall, something will stick. AFAIK, there were never any singular prosecutions for constructive intent, just confiscation of the non compliant part and the weapon it went to.