Directly from Hawaiian Airlines 'Contract of Carriage Rule'.
Shooting Equipment (Sporting Firearms)
Items of shooting equipment will be accepted only as checked baggage subject to the conditions and charges specified below. For the purpose of this provision one item of shooting equipment is defined as (1) one bag and may include up to but not more than, 5kg (11 lbs) of ammunition. Normal baggage size and weight limits apply.
Conditions of Acceptance
Firearms must be unloaded and placed in a suitable container. Firearms must be packed in (1) a manufacturer's crush-proof type container, manufactured specifically for the firearm, or (2) a hard case. Baggage containing handguns must be locked with a key or lock combination in possession of the passenger only, and the bag must be of hard side type. Baggage containing firearms will be transported in an area, other than the cockpit, that is inaccessible to passengers.
Ammunition must be packed in the manufacturer's original package or securely packed in fiber, wood, or metal boxes.
For transportation to/from locations outside of the United States acceptance requirements of the host government apply and must be verified upon acceptance. The passenger shall comply with all laws, regulations, orders, demands, or travel requirements of countries to be flown from, into, or over, and with all rules, regulations, and instructions of carrier. Carrier shall not be liable for any aid or information given by any agent or employee of carrier to any passenger in connection with obtaining necessary documents or complying with such laws, regulations, orders, demands, requirements, or instructions, whether given orally, in writing, or otherwise, or for the consequences to any passenger resulting from his failure to obtain such documents or to comply with such laws, regulations, orders, demands, requirements, or instructions.
Charges
When in excess, firearms will be subject to normal excess baggage charges.