Medal of Honor

During Comprimised

You are given an M60 machine gun. Whilst you are heading to the second extraction you will encounter more than 15 enemies on route. Just kill the 15 needed and the achievement will unlock

I am sure but when you get to the helicopter the tail gun you control may also be an M60,and if so you will have more opportunity to get the 15kills needed

Thanks To REDZERO UK, The kills also carry over if you die and have to restart the checkpoint...

If you are going to vote negatively please leave a comment as to why, so i can make my solutions better

just to add on. you don't have to get all of these kills on one play through. I hadn't read all of the achievements before I went through this level the first time, and so wasn't too concerned about killing everyone I saw. On the second time through, I got the achievement on the first batch of bad guys you come through, and that was only about 4 kills, so they do stack.

From x360achievements:

When you are doing the objective "Move to Secondary LZ", Voodoo will dislocate his arm. When he does, you will get his M60. Now all you have to do is get 15 kills.