New Jersey and "non"-firearms.

Can someone give me some guidance on existing legislature in new Jersey regarding things like airsoft and pellet rifles?

My girlfriend's mom wanted to buy one online, and Amazon refused to ship it to NJ. This started a discussion about whether they needed a FOID permit in order to buy them, or if they just could not be mailed.

My Googling has not been very good, and what I have found has been either a) conflicting or b) unintelligible to me.

Not looking for legitimate legal advice, obviously. Just some insight and maybe some layman breakdown of the laws.

Thanks