So you have to pray it even drops an exotic at all which is 25-33%. Then you have getting the piece that you want which is 1/8 if you were to look at Titans for example, which is a 12.5% chance. Then finally you have the chance of getting an actually decently rolled chest piece which is something like less than 1%. You need every single star to align, a hope and a dream to get what you want and that is IF you even have your discipline armourer mod on. Without it the RNG gets even worse (couldn't imagine an RNG like 0.000182920...etc to be even worse but here we are). Master difficulty needs to have a drop rate of 60% and Legend needs to be 30%. I'm not going to sit here all day twiddling my thumbs for a chance to get the thing that I want, hidden behind dozens of layers of RNG.