Are pistol grip crossbows illegal in N.H.?

Someone told me that they are, but I cannot find information relevant to pistol grip crossbows, only normal crossbows... so I cannot be absolutely sure that they are legal or illegal. Can someone tell me with certainty their status in relation to N.H. state law so that I can be sure before I get one (if I get one... that issue is tied up with the legality).