My contribution: No reserve ammo, only allowed your current magazine on primary and secondary, det and traitor weapons not allowed.
This one is impossible as a huge does 15 damage per headshot. Either that or hit someone in the head 5 times for 1 kill. Just not a challenge you can do right.
Shoot 10 individual players (without killing them) with the newton launcher in one round, without being called out/KOSd.