N.H. Rev. Stat. § 159:1
Pistol or revolver, as used herein, means any firearm with barrel less than 16 inches in length. It does not include antique pistols, gun canes, or revolvers. An antique pistol, gun cane, or revolver, for the purposes of this chapter, means any pistol, gun cane, or revolver utilizing an early type of ignition, including, but not limited to, flintlocks, wheel locks, matchlocks, percussions and pin-fire, but no pistol, gun cane, or revolver which utilizes readily available center fire or rim-fire cartridges which are in common, current use shall be deemed to be an antique pistol, gun cane, or revolver. Nothing in this section shall prevent antique pistols, gun canes, or revolvers from being owned or transferred by museums, antique or arms collectors, or licensed gun dealers at auctions, gun shows, or private premises provided such ownership or transfer does not conflict with federal statutes.
RSA 159:1
1923, 118:1. PL 149 :1. RL 179:1. RSA 159:1. 1967, 220:1. 1992, 273:1, eff. July 17, 1992.