The Outfit

Midway through Mission #3 (Yo Adrienne!), you will come across a row of anti-tank guns pointed across the river and be warned that an enemy convoy is approaching. Mount up onto one of the guns and watch for them to approach from the left side on the opposite bank of the river.

The trucks are pretty easy prey, you can probably hit them on the move. The armored vehicles are tougher, as they move more quickly. Try to hit them in the moments that they sit still. If there is a lot of wreckage on the road, it seems to take them longer to get across.

You need to destroy eight vehicles in the convoy, which allows you to miss two or three, so don't fret if one slips by - you don't need to get them all. You can reload the mission and try again if you miss out.

The Achievement will unlock once the entire convoy has arrived.

When going through this game which I am highly recommending doing is using the Xbox Achievements road map made by CienPR, when you hit each level of the story just hit CTRL+F on the page and type the Mission you are on, and you will find the achievements you need to look out for and how to do them on each mission. There is about 2 each mission, and there aren't any videos which I would be posting if I could find some, but I guess this game isn't popular enough.

Again credit goes to CienPR, good luck and have fun

Road Map:

http://www.xboxachievements.com/game/the-outfit/guide/#