"Assault Pistol" means a semiautomatic pistol which accepts a detachable magazine and which has two or more of the following characteristics: an ammunition magazine which attaches to the pistol outside of the pistol grip; a threaded barrel capable of accepting a barrel extender, flash suppressor, forward hand grip, or silencer; a shroud which is attached to or partially or completely encircles the barrel and which permits the shooter to hold the firearm with the second hand without being burned; a manufactured weight of fifty ounces or more when the pistol is unloaded; a centerfire pistol with an overall length of 12 inches or more; or is a semiautomatic version of an automatic firearm.

So this means that if we get a fixed mag California receiver that was never a made or registered as a rifle we can make AR format pistols out of it?  Does HPD throw a fit when we register it?

Waiting for Suka, hes the regional expert on the loopholes.

So this means that if we get a fixed mag California receiver .............. we can make AR format pistols out of it? Does HPD throw a fit when we register it?

That is correct, I spoke with a SGT. and he was amazed that such a loophole does exsit. They HPD will take you to another room and , You will need to show them the operation of the "PISTOL"

You will need to prove beyond a resonable dought  that it is NOT a :
semiautomatic pistol which accepts a detachable magazine
thus : a single shot, bolt action, permantly fix mag (by welding or silver solder) is acceptable.
I have a copy of the official BATF letterhead  that HPD made a copy of.

that was never a made or registered as a rifle

This is a federal reg. under BATF.  HRS does not cover that.  but yes a virgin reciever.

How do you get a virgin receiver?  Doesnt HPD require FFLs to register all firearms with them when they arrive?  Does the FFL just have to register the receiver as a pistol instead of a rifle and thats it?  How do I get a BATF letter?

I'd assume you are not up to speed with Federal Firearms Laws.

ATF P 5300.4 - Federal Firearms Regulations Reference Guide

ATF P 5300.5 State Laws and Published Ordinances - Firearms

How do you get a virgin receiver?
You  can make your own  reciever or buy a commercial "Taxed"  reciever (100%) .  However, it must be a "pistol" on your 4473 form.

Doesnt HPD require FFLs to register all firearms with them when they arrive? Does the FFL just have to register the receiver as a pistol instead of a rifle and thats it?
A reciever is nither a Rifle or Pistol. it is registered as " RECIEVER ONLY" at HPD. It must be reg on the 4473.

How do I get a BATF letter?
Write them a letter with your question and wait 3 month for a reply. However, they only address Federal Regulation. Not individual States. You will need to contact the Hawaii Attorney General Office for State Laws. (they do not reply)

Thanks a million for your quick response SUKA.  I have something to think about now for my next AR build.  Maybe a FAB10 receiver would be just the ticket.