Kill 4 enemies in a row using multi-pistols. [Bronze / 20G]

First off, craft all pistol holsters. You can buy the required crafting items from any general store if needed. So you don't have to hunt down the animals on your own. Also buy and equip the "cannon-barrel pistol" for one-shot kills. All you need now is a group of at least 4 enemies. You can do this pretty much everywhere. Just walk up to them with the pistols selected in your weapon wheel and press triangle (PS3) / Y (X360) without aiming manually. Each shot should kill an enemy and this trophy / achievement is yours.