Red Dead Redemption
95 Achievements
1,500
85-111h
Headhunter
Kill 5 players via headshot in a single Shootout or Gang Shootout.
10
How to unlock the Headhunter achievement in Red Dead Redemption - Definitive Guide
Alternatively if you have sadistic friends who stand in a line, and a sniper rifle, I reckon you could get it done in 2/3 shots. Maximum efficiency...
You can either do this online or with a friend. Make sure you're in a Shootout or Gang shootout game mode and achieve five headshots within the match. While aiming at other players, lock on to them with the push up on the to aim for their head. If you don't already do this you should as it's an instant kill with most rifles.
If you take cover a lot and stay still the other players on the map won't be able to see your position. This will help you pick off the odd person running around on their own trying to snipe others.
See "Call it a Comeback!" for boosting information.
This trophy can be done on the same player over and over. This trophy has be in a Shootout or a Gang Shootout match. Just aim for the head and it will unlock after your fifth headshot kill. It doesn't have to be right after each other, just has to be in a single competitive shootout match.