Rodney

What is IR? IR is the voltage drop (current times resistance) in the circuit that the current is flowing in. The predominant one is the voltage drop between the battery and receiver (the resistance in the switch contacts and wire between the receiver and the battery). Say there is a tenth of an ohm and your have two servos that instantly demand 2 or 3 amperes surge (not unreasonable on digital servos) then you get at least a 0.6 volt drop in supply voltage as seen at the receiver power buss. Now let that resistance increase a bit by using to small a gage wire or getting some corrosion in the switch and the problems quickly get large enough to cause a malfunction due to voltage drop at the receiver. So, the problem is probably not the gage of the wire between the receiver or power box to the servo but the wire and switch between the battery and and the receiver and of course the internal impedance of the battery which adds to this resistance.