Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This Build can work in mid and laning. He can support well and still have lots of DPS. With this build his (Q) Mystic Shot will still be viable.
For the Rylai's you will sell the Philosophers Stone.
Q is good for early farming and damage. After Ezreal's monster buff, his Q hits EXTREMELY hard Early game. They can even hit hard after getting your Gunblade and Lichbane. The Lichbane's passive will add the damage to you Mystic Shot on hit. I have hit creeps for 1000 late game with this and even hit casters or chanpions with low armor for 400-500.
This build is obviously a Hybrid build after I looked at it =P. There was a discussion over it and it has been solved. Rate well.
In game name: Bunny Wabbit