Thanks for the replies, there’s a lot to deal with makes me want to consign guns or sell to gun stores if that’s even possible lol
Some advice on here is based on HANDGUN transfers (like signing the permit and turning it in). Since you specified long gun, those comments, while accurate, are just muddying the water for you.
I included some handgun steps in my comment for contrast, but specifically stated it was different from long gun.
Long gun transactions are WAY simpler than for handguns. Don't let the confusion on here get you nervous. Just remember these things:
1. You need to see the buyer's LG permit to acquire and his ID, to make sure they match. If the terms are agreeable, and you have no suspicions about the buyer's identity, I'd say the deal is ready to be completed.
2. A written bill of sale is fine, but you can use online forms if you want. This paper does 2 things: (1) acts as a receipt for the buyer since they are likely giving you cash, and (2) gives you a record of where your firearm went if anyone ever asks. I would copy your registration form's control number (usually starts with a "G-") onto the bill of sale, so you don't need to worry about making redacted copies for HPD. All they need is the number and the seller's name to look it up.
3. You need to meet in a place that reduces risk, both of being reported/caught showing a gun in public, and for your safety if you don't know the buyer. Murphy lurks around every corner. Just because everybody else that transacted a gun sale in Zippy's parking lot had zero problems doesn't mean you won't have a bunch of Cops walk out of the restaurant while the buyer inspects the firearm.

4. Once you have the money, the buyer has the weapon, and you both have a bill of sale, the transfer is complete.
5. Registration is the last hoop to jump through. The seller has to notify HPD of the transfer within 5 (?) days in writing (the Hawaii county PD website has a form letter you can use as a template), and the buyer has 5 days to register. Kinda like DMV, where both parties have to notify DMV of a title transfer.
It's really simple. Use common sense. If the buyer asks you to meet behind Femme Nu when they get off work at 3AM, I'd probably find another buyer!
