EP drop protection numbers/percentages?

Does anyone have any concrete details (from Bungie specifically) explaining how the weapon drop protection works? I'm sitting at 38 clears according to the "Escalation Expert" triumph and have not received any of the weapons. Over the last two hours I've seen three people (two of whom were largely worthless to the players participating in the encounter) get the shotgun. I understand that's how RNG works but...feels bad..!

edit: nvm i got it!