Never heard of NIJ either. From the pic you posted, it looks like a Female JIC to NPT adapter. JIC and ORB threads are the same. Same dimensional specs and one will thread into the other. However the seal is different. The ORB male threads dont have the 37 degree seat and arent normally long enough to tighten up the swivel anyway. And the way it looks like the o-ring is bulging out, it looks like you have a JIC fitting, That bottomed out on the o-ring, but is incapable of sealing at the swivel. With a JIC swivel fitting, once tight, it should no longer swivel. The joint where it was leaking at the swivel, was it still loose and free to spin?