This Xbox 360 controller mod will allow you to fire single fire/semi-automatic gun in Call of Duty as if they were fully automatic.
Step 1: Take out screws
The parts you will need are a Xbox 360 Controller, T8 Tamper Proof drill bit (found online), solder and solder wire, drill, box cutter, metal wire, and a Momentary Push Button (bought at RadioShack).
First take out the seven screws in the back of the controller. There is one screw under the barcode where the battery pack goes. Remove it with the box cutter. Use the T8 drill bit to remove the screws.