Yes, you would need a FFL or have a friend who runs a gunshop to do what basically amounts to brokering the transaction.
The purchasing side needs the broker to send a copy of their license to the purchasing party (background checks on you etc, just like if you were buying it from the store) and then they make the purchase and you acquire it from the gun dealer and is what the process amounts to.
Basically to run a gun sales/trading site you need to be or be very close with a licensed gun dealer and have a lawyer to check your process (if you are doing anything other than providing meeting grounds for folks who will later meet up in person and handle the interstate sales process themselves or f2f sales in state). In a perfect world you would have a licensed gun dealer in each state participating in your site to network the inbound sales process.
This is definitely an area you should stay well away from playing with until you secure a FFL and even then speak to a lawyer concerning your business model and location of you/your FFL holder. Gun laws vary wildly from state to state.
When I say check the process...I am talking about having a lawyer check out the process you set up on your website to foster the sales/classifieds etc to protect your own rear but at the end of the day to actually receive a gun from out of state you need to be a gun dealer and there still is no way to get around that so in reality the one time you hire a lawyer to make sure your site's process is legal is way cheaper than lets say paying someone in each state to receive firearms for each out of state purchase.
Facebook did it for years with no FFL and none of these other "social networks" have FFL either ,
i think what we need to look at is the grey area that is ... "USER GENERATED CONTENT" allowing the transaction of firearms is as easy as stating that they "SHOULD" use proper FFL channels to complete the purchase , i personally have bought and sold 10+ firearms via Facebook gun groups that are now defunct.
if someone posts something illegal on Facebook.... Facebook isn't liable for it under the term "USER GENERATED CONTENT" ??
Here is the disclaimer on my site ... BECAUSE MY SITE RIDES A THIN LINE TO BEGIN WITH..
All content made available by this website and any opinions, advice, statements or other information contained in any messages posted or transmitted by any third party are the responsibility of the author of that message and not of My Militia (unless My Militia is specifically identified as the author of the message). The fact that a particular message is posted on or transmitted using the My Militia web site does not mean that My Militia has endorsed that message in any way or verified the accuracy, completeness or usefulness of any message. We encourage users of the site to report any objectionable message by using the "report" function.
MY MILITIA IS NOT MONITORED 24/7 ~ ILLEGAL CONTENT IS STRICTLY PROHIBITED ~ USE AT YOUR OWN RISK
There is something to be said about this... there is some PDF documents that are discussing Illegal activity ... upon my harvesting of content i skipped over these items.... then later in my trials i seen them posted else where.
So I'm like WTF if they can post this and its ok why can't I?
instead for hosting the files locally i used scribd as a layer of protection... i have many many examples. The content is flat out Illegal to perform the instructions but the instructions them selves are not illegal ... how you like that!?
You're trying to match up a buyer/seller only, correct? It would be their responsibility to eventually meet up at an FFL. You're just posting an ad like Craigslist would. But I guess it would depend on your personal risk tolerance and legal team.
I sent an email to my NRA contact about it ... the site Gun District has a little 4 lines of text that says they are not involved with the transactions but suggest you do legal transfers. i bet you thats all we have to do to allow this