I was browsing an older question recently thanks to a duplicate, and I found that the accepted answer for that question said something odd:
Sounds obvious. When you have advantage, there is a good chance for you to hit. If you use GWM/SS, you lose that advantage.
(Emphasis Mine)
That struck me as odd, so I went to look at the (relevant) Sharpshooter feat text, which says:
Before you make an attack with a ranged weapon that you are proficient with, you can choose to take a -5 penalty to the attack roll. If the attack hits, you add +10 to the attack’s damage.
As you can see, the feat's text says nothing about losing advantage when one uses the Feat and, as a side note, the Great Weapon Master feat referred-to in the answer also lacks any mention of losing Advantage when using the feat.
Is there something I'm missing here? What about Advantage-based conditions like Sneak Attack?
Best Answer
It effectively removes advantage for the mid-range of a d20.
It's not that you're removing Advantage, but that the advantage is about +5 and is cancelled out by the -5 from GWM/SS.
There are two bases for this:
Advantage often acts as a +5
+5 is used when calculating passive advantage.
Advantage itself remains
Note that the math is the only thing that applies here with regard to +/-5. You still actually have advantage with all the rights and privileges granted by it (including a better chance to crit.)