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.
Any builds I have ever posted I've used multiple times an have had at least 1 game wit 20 kills, its very easy to have a K/D of 10:1 with this build.
Starting out if your lucky you can be critting pretty often I try buying Brawlers Gloves to begin with which sets me at 22% crit chance at level 1 and some mana pots to spam Parrrley.
Make sure you keep an eye on teammates as Cannon Barrage can be a team asset.