Ammunition and magazine laws in Hawaii

(g) Except as provided in section 134-5, no person who is under the age of twenty-one shall own, possess, or control any ammunition for any firearm; provided that this subsection shall not apply to a person in an exempt category identified in section 134-11(a).

§134-8 Ownership, etc., of automatic firearms, silencers, etc., prohibited; penalties. (a) The manufacture, possession, sale, barter, trade, gift, transfer, or acquisition of any of the following shall be prohibited: assault pistols, except as provided by section 134-4(e); automatic firearms; rifles with barrel lengths less than sixteen inches; ghost guns; shotguns with barrel lengths less than eighteen inches; cannons; mufflers, silencers, or devices for deadening or muffling the sound of discharged firearms; hand grenades, dynamite, blasting caps, bombs, or bombshells, or other explosives; or any type of ammunition or any projectile component thereof coated with teflon or any other similar coating designed primarily to enhance its capability to penetrate metal or pierce protective armor; and any type of ammunition or any projectile component thereof designed or intended to explode or segment upon impact with its target.

(c) The manufacture, possession, sale, barter, trade, gift, transfer, or acquisition of detachable ammunition magazines with a capacity in excess of ten rounds that are designed for or capable of use with a pistol shall be prohibited. This subsection shall not apply to magazines originally designed to accept more than ten rounds of ammunition that have been modified to accept no more than ten rounds and that are not capable of being readily restored to a capacity of more than ten rounds.

(x)(1) It shall be unlawful for a person to sell, deliver, or otherwise transfer to a person who the transferor knows or has reasonable cause to believe is a juvenile—
(A) a handgun; or
(B) ammunition that is suitable for use only in a handgun.
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(5) For purposes of this subsection, the term "juvenile" means a person who is less than 18 years of age.

Small Arms Ammunition: Ammunition is classified as a Division 1.1, 1.2, 1.3, or 1.4 explosive, depending on the degree of hazard. Ammunition that is regulated as a Class 1 explosive and designed to be fired from a pistol, revolver, rifle, or shotgun, as well as associated primers and blank cartridges (including those designed for tools) and propellant powder for use in any firearm, is prohibited from mailing.
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Shotgun Hulls, Empty Casings, Nonmetallic Shotgun Hulls, or Casings Without Primers: These articles are not classified as explosives or hazardous materials under 49 CFR and, therefore, are mailable, subject to the applicable mailing rules (refer to 224).