OP, lots of reading to do, if you're not already familiar with the NJ Assault Weapons Ban, and it's current laws. Info below:
http://www.state.nj.us/lps/dcj/agguide/assltf.htm
http://www.state.nj.us/njsp/info/pdf/firearms/njac-title13-ch54.pdf
http://smartgunlaws.org/assault-weapons-in-new-jersey/
Your most valuable resource, no schit, will be right here:
http://www.ar15.com/forums/f_8/50_New_Jersey.html
No kidding man - do your homework first. You're in one of those states where you can seemingly "built something innocent," only to find out that you've just committed a state felony... NJ is some scary schit...