Heading 9301 covers weapons designed for military use, while heading 9303 covers sporting, hunting, and target-shooting shotguns and rifles. The distinction rests on the article's design and principal use; features such as selective-fire capability or military-specification components can push a firearm into 9301. CBP rulings and ATF guidance both bear on this determination.

ATF Form 6 (or Form 6A for re-imports) is required for most commercial firearm and ammunition imports. Military-category items may additionally require a State Department import license. Edged weapons such as swords (9307) generally do not require an ATF permit but may be subject to state or local restrictions. Consulting a licensed customs broker and ATF directly is essential before shipment.