On the Island of Los Muertos in the south is a pier that extends into the water (west of the Ferris wheel pier). On that pier there is a circle of explosive barrels that curls around a building on the pier. Shoot it, then run north and as the pier allows you to, go east or west. Look to the west where the apartments are located. There is another set of barrels in a row. Shoot them. Complete this process a few times to get the Chain Banger achievement.
Note: This trick requires the downloadable content that includes the new vehicles. Go to the Agency and get the armored car that shoots the missiles. Drive through door two into Volk Drive until you are just outside of the tunnel. Hold B or LB to shoot the rockets. The rockets will keep firing and you should get the achievement.