Not Working?
OK, my son and I went in to Sierra 117 to get the 15,000 points and the 10 headshot achievements. We enabled meta scoring by activating team scoring and activated 4 skulls (Thunderstorm, Famine & Fog). We went through the level and scored 16,000+ points and each had well over 10 headshots but received neither of the awards. The skill level was set at normal. What gives?
Unlimitedguy5-You mentioned that you can kill the marines before activating the bridge, but where are you supposed to get a sniper rifle?
Do you have to get 10 headshots in a row?
I got the same problem too. I made a spree of like 20 headshots in Crow's Nest on Easy and didn't get the achievement. I enabled Grunt Birthday Party and all the gold skulls except for Iron and Black Eye.
Do I have to make a spree at Legendary or something like that? Rezo 'Scratoqee 
(Talk) 18:12, June 10, 2010 (UTC)
Read the article. It will only work by getting headshots on Brutes or Jackals.--Shade 18:20, August 5, 2010 (UTC)