I went the "safe" route myself, obviously. I built my virgin receiver into a pistol while waiting on the stamp and only upon getting the stamp back did I install a stock on that receiver. I agree that it's better safe than sorry, but I'm still of the opinion (not betting my lack of a criminal record on it) that the concept of constructive possession of an AR15 SBR is a fairy tale. I'd be interested to find a case where someone was charged with that where there were not other circumstances (criminal took the illegal SBR apart). Wanna kill these ads? We can help!