N.H. Rev. Stat. § 644:14
If any person shall sell, barter, rent, lend, or give an air rifle or paint ball gun to a person under the age of 18, without the written consent of the parent or guardian, as the case may be, such person shall be guilty of a violation. Air rifles and paint ball guns may be used in New Hampshire only in the home of the person under 18 under parental supervision or on an approved range under responsible adult supervision. Air rifles or paint ball guns may be possessed by a person under 18 only in his or her own home under parental supervision or on the way to or from an approved range that is under the supervision of a responsible adult such as an instructor in gun safety or marksmanship.
RSA 644:14
1971, 518:1. 1999, 44:1, eff. Jan. 1, 2000.