Hi Cap mags in Hawaii

Actually there is and has been an exemption for hi-cap magazines for theatrical use; they are just not mentioned specifically. They are covered under 134-2.5 of the HRS and are viewed as "part of the gun or system"
All that is needed is a letter from production justifying the need for firearms and stating who will be responsible for them, storage facilities, security, etc. and of course a film permit.
The applicant, you, MUST first have an FFL and fill out the state permits for possession--basically the same as California. When the firearms/magazines arrive they must go directly to the police dept. for inspection. The gun unit prefers to have a list/manifest with descriptions and serial numbers in advance. It will make the permit approval and check-in process much smoother.
I've shipped/transported hi-caps/firearms to Hawaii since the early days of Magnum PI without any problems ever. Email me if you need contacts there.
Hope this helps

4570guy