In this particular case Christie is probably very happy. He knows he is not going to lose a primary challenge to this guy, and he can then claim during the general election that he's a true "moderate" as evidenced by the fact that right wingers tried to defeat him in the GOP primaries. In a blue state like New Jersey that just helps him.
Well, New Jersey residents who are conservatives and support the Second Amendment can use the threat of supporting this guy as a lever to move Christie on the flood of anti-Second Amendment bills recently released by the Assembly Law and Public Safety Committee.
Christie can either veto them openly or let them die on his desk.
Christie is ambivalent on the Second Amendment. Its a very important issue here to gun owners.