Thanks for the input guys it is greatly appreciated.
I will look into the batteries suggested I would like to just confirm the size of my buffer tube however I dont have an accurate measuring device at home so that might wait a few days.
@ Cactus - After review of the diagram my wiring was different. My positive feeder from the battery was sharing the same contact point on the switch as the wire from the MOSFET. Is this the cause of the short? How would it be different if the positive feeder is connected to the motor side of the switch as shown (obviously because the diagram says so but and understanding goes a long way)?