Let me tell ya how it goes. It's not as bad as they're making it out to be. I guess it depends on where you're coming from.
100% registration. when you move in i think you have 10 days or so to take what you have to the honolulu downtown hpd and register it. they just type up a form and you get a copy.
highway, only time firearms can be in the car is when you are going to or from the range or hunting or trading, making a sale or what ever.
no concealed carry.
restrictions. basically the only thing you can't have is what are considered assault pistols. tec9, uzi, cobray, you get the picture. if you had them here already when they banned em, you can keep em but not transfer them. so when you die they go to the state or out of state tranfer only.
you can have ar15, ak, m1a, sks, and alot of other fun stuff.
magazine restrictions, basically it goes like this. no mags over 10rds if they fit in a pistol. like ar mags ya can't have cause they can fit in an ar assault pistol. 10/22 high caps ya can't have cause they fit in a tec9. get where i'm going? you can have m1a high caps, mini 14 high caps, ak high caps. so long as they don't make a pistol that will accept the rifle mag you are ok. if you have high caps they're supposed to be blocked to only hold 10. not a plug either but like a rivet. misdemeanor to possess high caps(unless blocked), felony to put em in a firearm.
purchasing, long guns require a long gun permit. 14 day wait, after the 14 days you get a permit that is good for one year. you can walk in any store and buy long guns on the spot with that permit. you then have 3 days to register what ever you bought. after one year, get new permit.
hand guns is 14 day wait and background check. it goes like this. go to the store. show proof of either hunter ed or nra instruction course. pay for firearm. take hunter ed or nra course and gun info from the shop to hpd. apply for permit to aquire that particular handgun. after 14 days go back hpd pick up approval. take approval back to shop and pick up already paid for firearm. take firearm back to hpd and register it.
1st time purchase whether long gun or hand gun pays one time $25 fbi background check fee. if you bring guns in you don't have to pay. just register them.
there is a great public shooting complex at koko head crater. they have silouette shooting, rifle range, hand gun, trap, skeet, cowboy action, and ipsc.
hope this helps.