Is it legal for me to sell a gun to someone in NY without going through and FFL or is it required it goes through a transfer?

Yes it legal in NYS to transfer a long gun (or handgun with a PP/P.O.) in a private transaction as long as you do not transfer it to a prohibited person as defined under Federal and NYS law.

thanks

It is also legal to ship firearms within the states borders to private individuals. With no need for a FFL transaction.

Quoted: Quoted: It is also legal to ship firearms within the states borders to private individuals. With no need for a FFL transaction. Really?

Yes AFAIK it's legal but unless you know the person you're doing the transfer with I wouldn't do it.  If you do a transfer like this make sure you ship it with adult signature required for delivery.

two things,
first off - you cannot KNOWINGLY sell a long gone in state to a prohibitted person.
Dunno how far that goes, but it's a bit of seller protection - For mailed transactions, I just ask for a paper that says "I can legally buy and own guns and this rifle in particular XXXXXX, signed XXXXXX"  Along with a copy of NY license for proof of residency.  BUT in person, I just ask all that crap.
second, postal code says ONE THING about shipping long guns within state.  The sale must comply with the 1968 GCA.  that's it.  (oh yeah, no ammo in same box. hell, no ammo period USPS)

So yes, you can sell a gun w/in the state no ffl, AND you can send it USPS.
(one of the guys i shoot with works the counter at usps two blocks away from me.)