Exotic drops arent exactly all the that rare. The problem being is the loot table. I believe that the loot table changes with the reset or every so often. This could explain why you repeatedly get the same exotics for a week or two or three running. I believe that it changes, and that they become weighted of sorts. Example, for one week I received 3 hard lights from various activities. Same with the Plan C. I received 3 over the course of a two week period. Gjallarhorn I received 2 in the same week. Usually when I receive one, I'll get at least one more in that same period of time. Only weapons I haven't received duplicates of is the Red Death, and universal remote. I don't believe there's any way to prove my theory. Speculation at this point, but from what I've seen and read, it appears your loot tables changes every so often, and that certain weapons are weighted each change. That's explains why some guardians received 6 of "x" and none of "y." Statistically speaking, there's 16 exotic weapons from drops. This excludes the 5 bounty exotics and PS exclusives. So there's a 1/16 chance of getting what you want. I've received at least 8 truths, and duplicates of most every other exotic. If it was truly random, Id find it that you wouldn't get the same exotics on drops each week. I wouldn't have expected 3 hard lights that one week. That's a 1 out of 4096 chance of that happening. Although in actually it's always 1/16 chance. Repeated receiving the same exotic in a short period doesn't seem likely unless they are weighted and change every so often.