So let's say you register a TC Encore frame as a SBR, but you later want to swap the bbl on your stocked sbr frame with a 26 inch long VR Shotgun bbl, have you just made a illegal SBS because of the frame being registered as a SBR or does it resort back to it's original none registered condition when not being used as registered ???? Just wondering what our NFA guys on here think about this... I know I would have to have a letter written to the powers that be but what do you guys think about this ???