I was hooked on that type of scout rifle in the beginning with the FWC scout, can't remember it's name, in vanilla destiny. Then, after vault, got a Vision of Confluence. Then got the Fang of Ir Yut in The Dark Below. Then midway through HoW ended up getting my hands on a Gheleon's Demise, slower firing but hard hitting, and haven't looked back. For TTK, I originally used the Last Extremity, an engram one with Firefly in the same archetype as Gheleon's. Then last week, got the Cocytus with Casket Mag for 16 rounds in the chamber. I wish it had some other perk rather than Icarus but it was definitely better than my Last Extremity just on bullets in the mag alone. You can buy a Last Extremity to try out the archetype but the vendor one doesn't have a really good roll like the Hung Jury does and if you didn't buy a Cocytus package two weeks ago, you pretty much missed your chance at it.