Assuming this isn't a troll post, LDR is a Dark Below sniper rifle that is no longer obtainable from vendors because HoW switched out vendor weapons and armor. You can run ROC strikes or Eris missions and hope an engram gives you one. Felwinter's Lie is a shotgun that can only be obtained through the Iron Banner. If Lord Saladin happens to be selling it then you can buy it at rank 3 or 4(I forget which). If he's not selling it, then you'll have to play Iron Banner and see if it drops as a reward.