Rise of the Tomb Raider

I won't take any credit for this video just hope it helps you get the achievement

In expedition, Mode: replay chapters - elite, Fase: the tower, Level: adventure.

After you defeat the first guys, you will see a bridge with somes barels there..

Wait until there are 3 guys there and 2 guys on floor..

When the 2 guys on the floor show up, shot on barrel and kill the guys on the floor and the achievement will be yours..

Since the barrel solution doesn't work anymore-

Expedition- Mode: replay chapters elite, Level: The Acropolis, Difficulty: Adventure.

Head down the path towards the quest marker and into the cutscene ahead. After skipping/watching the cut scene, shoot the legs of the two guards in front of you (don't kill them). After attracting their attention, back up to the area before you triggered the cutscene and hide behind those crates on the right hand side. Stay there until eventually a little mob of guards will swarm the entryway where the cut scene happened and you can just mow them all down. Easy-Peasy

Note that this is a great level to get the other achievements below because there is a checkpoint you can reload over and over after the cutscene:

EDIT (16/12/2016): a Title update may have blocked the possibility of using the grenade launcher attachment for getting this achievement. Even tough, the spot described on the solution is a great option to have a bunch of enemies together to finish off them quickly...

First of all, I can confirm that using the grenade launcher attached to the rifle will count for the achievement. That's how I got it!

Now, for a good place to find 5 enemies together, you can use the same spot described by SandMan NL1 on the solution for the Chemical Warfare achievement. If you have finished the game, chose Replay Elite at the Expeditions menu. Select "Research Base". You can set any challenges and cards, it doesn't matter.

You'll have to advance on the level till you get to a base camp near a frozen lake. Once there, dive in the lake and come out through a gap on the ice. There will be two enemies. Drown one of them and kill the other with stealth. Right after this you get to a checkpoint, so if you mess the things up you can reload.

Rigth up front you'll see a red truck and just before it you can find some bottles. Use one to craft a molotov and throw it in the front of the truck. Step back a bit and have your rifle ready. Use the grenade laucher in the group of enemies that will come out from the back of the truck. There will be up to 6 foes grouped together so you'll have more than enough for the achievement. If the explosion doesn't kill all of them, simply shoot another shell or fire bullets to kill the remanents. You have 10 seconds to perform the five kills, so if the explosion have killed half of the group you'll have plenty of time to shoot down the others.

Be aware: there's 8 enemies in this area, 6 of them will come grouped after you throw the molotov, but the other 2 will come a little bit latter. If you kill all 8 enemies another checkpoint will be reached and you'll not be able to reload in case you didn't get the achievement.

Obs: after diving in the lake, if you drown one of the enemies near the ice hole and got spoted by the other, he'll shout and the group of enemies near the truck will come after you. In this case, you'll have to be quick and turn around after getting out of the water to shoot at them...

Hi, after my natural Language is German and i bet more Germans are on this Site i will add my solution in german :)

Dazu hab ich dieses kleine Video inkl. Erklärung gemacht ich hoffe es hilft euch

Once you have upgraded any rifle significantly it will deal a lot of damage, mean you can get one or two shot kills. Just enter an area with at least 5 enemies in close proximity and then you should be able to take them out very quickly and get this achievement.

If you can't get it in the story any of the level replays in Expedition Mode with enough enemies can be used. I happened to replay "The Tower" level as it has groups of enemies in quick succession right at the beginning and doesn't last long.

Another, alternate and story based place to get it is, near the end of the game when you're: