There is no magazine restriction on carrying a long gun in general, although there is one regarding how many rounds you can carry while actively engaged in hunting.
207:3 Lawful Methods of Taking. –
I. Wildlife shall be taken in the daytime between 1/2 hour before sunrise and 1/2 hour after sunset with a gun fired at arm's length or bow and arrow, unless otherwise specifically permitted.
II. A full automatic rifle shall not be used at any time nor shall a semi-automatic rifle be used to which is attached a magazine or clip holding more than 5 cartridges, nor shall a full jacketed metal case bullet be used, either in its original form or any alteration thereof.
III. Paragraph II shall not apply to the use of .22 or smaller caliber rimfire firearms.
^^-- Interestingly, you can lawfully hunt with a fully-automatic .22 in our state if you read that law closely. 55 rounds in bambiwill surely shutit down. This of course would have to beregistered federally and I am not sure if there are any transferrable .22's out there. :celebrate
OC of a long gun in generalis legal. You cannot have a long gun loaded in a vehicle though, under any circumstance:
207:7 Hunting From Motor Vehicle, OHRV, Snowmobile, Boat, or Aircraft. –
I. No person shall take or attempt to take wild birds or wild animals from a motor vehicle, OHRV, snowmobile as defined in RSA 215-C:1, boat, aircraft or other craft propelled by mechanical power.
II. No person shall have or carry, in or on a motor vehicle, OHRV, snowmobile, or aircraft, whether moving or stationary, a cocked crossbow, a loaded rifle or loaded shotgun, or a rifle or shotgun with a cartridge in a magazine or clip attached to the gun.
III. No person shall have in or on a boat or other craft while being propelled by mechanical power, or in a boat or other craft being towed by a boat or other craft propelled by mechanical power, a cocked crossbow, a loaded rifle or loaded shotgun, or a rifle or shotgun with a cartridge in a magazine or clip attached to the gun.
IV. The provisions of this section shall not apply to law enforcement officers carrying guns in the line of duty.