I don't know why I own 5 Gjallarhorns, it is something wrong with the system of "random rewards"?. This is the way i got them: 1- In Atheon on hard the second time I beat him!. 2- In the Crucible by playing control. 3- In a Nightfall completed on Wednesday. 4- Defeating Crota on normal, when the Dark Below just were released!. 5- Another Nightfall but this time I defeated Omnigull on friday. On the other hand... I was looking for "Black Hammer" and after a lot of repetitive weapons i finally got it this week!. Dear Bungie crew: "Can you let me open a Gjallarhorn store in the Tower?" jajaja Regards from "Led Zeppelin Army".