OK I didn't know the quest line for the thorn. I haven't looked into getting it yet, not sure if I can just buy a new one from year one blueprints or if I actually have to do the quest. With the dot being 3 and the ridiculous amount of ghost bullets plus the new anti-dot artifact not really sure if I will. If they ever return it to its former glory of 21 points dot I might, even with ghost bullets, which bungie somehow blamed my connection for or the all out slap in the face where they tell me that I hallucinated ever firing the gun, I might get it. So good luck on that, oh yeah I noticed that I tend to get more keys if I already have one. Hey I read somewhere in these forums that the lower level Siva strike was dropping them at 1 in 2 rate verses the hard which he said was 1 in 5. Hope that helps you.