Armor build on Ekko doesn't seem very effective.
I just played a game as Ekko
, top lane, against an AD comp team:
My team was:

We were down at around 20 minutes and had no tank so I decided to go with a tankier build rather than full AP. I got:
.
The only person on the other team with any sort of armor pen was Lee Sin who had a Black Cleaver, other than that it was flat AD across the board (except Lux). For the most part this build worked pretty well for me but at one point I traded with Lee Sin 1v1, both at full build, and noticed that he chunked like 1/4 of my health with a Q/E combo. I disengaged afterwards but it didn't seem like my armor was very effective. I'm sure if i had more of an AP build I would have out-traded him, but since I chose to go with a defensive, bruiser build, I would expect to be able to last longer in a 1v1 than that. Obviously there were other instances throughout the game that I noticed this same stuff, but it wasn't so clear in teamfights.
I haven't gone and looked up exactly how armor and armor pen work so I suppose maybe I'm misinformed but I would think that +230 armor would shield more than it did. Anyone have any answers for me?