So i was playing a match and i hit the jett for 154. Isn't the max damage 150 ? Also sometimes it shows I gave 300 damage. So what does it mean?

We all know that recently they have been way more cheaters than ever before even in Unrated games. In the last 2 weeks I've met 4 cheaters and before that, I've never met any cheater once since the beta. The worst thing about this is th...