This is my first build so bear with me please :)

I REALLY wanted Caitlyn to be a viable champ ever sense i saw her announcement. I have tried a lot of different builds either attack speed, lifesteal, or armor pen ect. However the one main flaw with these one track builds is that i felt she was far to squishy even with massive lifesteal.

The point of this build is to make her dangerous hard hitting but also give her some survivability that doesn't depend on lifesteal.

Runes are pretty straightforward im going with attack speed mostly because you can tear through enemies with your black cleaver and the attack speed makes your passive more effective

These items may not be totally revolutionary or anything. However after a few games i found that Tri foce worked WONDERS with Cait.

The first major item should be the triforce or black cleaver i usually go with the black cleaver for the massive dmg and armor pen plus the attack speed makes harass and farming a breeze

However once you get your cleaver and triforce is when you will rip through champs. Plus chasing will be a breeze do to the slow from phage and attack speed from zeal.

After those 2 items its really up its really up in the air. Either you can go with a FM for the increased slow and survivability, or Phantom dancer for the attack speed and crits or just plain dmg with lifesteal from the Bloodthirster