I went into custom games with the BR and it still took 5 shots to kill. I was right next to enemy and all shots were to the head please help?
It was a server side update. Go play a slayer MM game and then go to customs, go to recent games and play that version of slayer. 
You’ll have to download the gametypes from the HaloWaypoint file share found below:
All the on-disc gametypes in custom games still use the older settings.