16" is the legal length in the states without a stamp or pistol lower. 14" in nothing more than my opinion is the shortest length a 556 is reasonably useful.
to be a legal sbr and you dont get to serve time in the "federal pound you in the ass prison" you need a NFA tax stamp. they cost 200$ and a 3-9 month wait after filling out and submitting the proper paperwork to batfe. check out the nfa/ffl subforum for more info on sbr tax stamps etc
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent