no 3sk?

i was playing a custom game with my brother on custom games just him and i. and we were testing the weapons and i saw that 3 shots to the head with pistol didnt kill my brother. now this was with all anniversary settings in slayer. so why is everyone saying that there are 3sks in the game? or is it only 3sks in matchmaking?

It’s still a 3 shot kill in customs.