This achievement while it may not specify it, comes at the end of the 'Dust to Dust' mission.
For the mission, you play as Captain Price and along with Yuri, start off in Juggernaut suits. Makarov has a small army to deal with before you reach the climax of the game, so deal with them with the following tips I point out below:
(Still in first week of release, so I'm not going to spoil the story at all, but above I've mentioned what you should expect to deal with throughout the mission)
Also, this achievement is for beating the campaign on any difficulty. Recruit is the easiest difficulty to achieve this on, Veteran the toughest. Regardless of difficulty here are some tips.
-- Take cover frequently when fighting enemies and taking damage. The harder the difficulty the fewer shots you can take.
-- Frag the enemies when several are in a group. Always a quick way to remove multiple threats at once. If you get lucky you'll earn the following achievement for this:
-- Always pay attention to the dialogue. Do what it says and don't try to rush things.
-- Don't get frustrated during the campaign if things don't go your way. There is a way to get through it.
There are 16 missions in all, plus the two minute sequence to begin the game. Enjoy the campaign, as it's very solid in my opinion. Easily has it all.