36 CFR § 2.4 - Weapons, traps and nets.
(a) None of the provisions in this section or any regulation in this chapter may be enforced to prohibit an individual from possessing a firearm, including an assembled or functional firearm, in any National Park System unit if:
(1) The individual is not otherwise prohibited by law from possessing the firearm; and
(1) Except as otherwise provided in this section and parts 7 (special regulations) and 13 (Alaska regulations), the following are prohibited:
(i) At designated times and locations in park areas where:
(B) The taking of fish is authorized by law in accordance with § 2.3 of this part.
(ii) When used for target practice at designated times and at facilities or locations designed and constructed specifically for this purpose and designated pursuant to special regulations.
(iii) Within a residential dwelling. For purposes of this subparagraph only, the term “residential dwelling” means a fixed housing structure which is either the principal residence of its occupants, or is occupied on a regular and recurring basis by its occupants as an alternate residence or vacation home.
(i) Traps, nets and unloaded weapons may be possessed within a temporary lodging or mechanical mode of conveyance when such implements are rendered temporarily inoperable or are packed, cased or stored in a manner that will prevent their ready use.
(ii) An individual may carry or possess an unloaded bow or crossbow when accessing otherwise inaccessible lands or waters contiguous to a park area when other means of access are otherwise impracticable or impossible if:
(A) The individual is not otherwise prohibited by law from possessing the bow or crossbow; and
(c) Carrying or possessing a loaded weapon in a motor vehicle, vessel or other mode of transportation is prohibited, except that carrying or possessing a loaded weapon in a vessel is allowed when such vessel is not being propelled by machinery and is used as a shooting platform in accordance with Federal and State law.
(1) When necessary to support research activities conducted in accordance with § 2.5.
(3) For employees, agents or cooperating officials in the performance of their official duties.
(4) To provide access to otherwise inaccessible lands or waters contiguous to a park area when other means of access are otherwise impracticable or impossible.