There is a big 560 page book available at many New Jersey sporting goods stores called "Nappen 2: New Jersey Gun, Knife & Weapon Law"
It appears to be worth the $24. I paid for it although I'm no lawyer.
The author's web site is www.evannappen.com and he posts updates to the book there as well.
New Jersey gun laws are complex and there are many "pitfalls and loopholes" Good luck!
-BB-