Before making assertions about physics, learn what you're talking about.
Voltage = Current * Resistance
Amps = Amount of Electricity flowing per second
Voltage = potential difference. Aka, the maximum possible output of electricity.
That is why you can be shocked with 355000 volts of electricity, and not die.
Migher amps= More spring compressing power.
More Voltage= Higher rof.
Voltage is how fast the electricity is moving, amps is the amount of electricity, So your gun was having 9 times faster of a curent, but small gun with an already small spring, does not need more amps, the Vulcan (presumably) would. So a balance would need to be found.
Also, 6 D batteries when wired in parallel have a voltage of 9, the same as a single 9v battery. If you are using 3 9 volts, the amps change. I = V/R. 27/R is larger than 9/R.
Let me reiterate: The only thing that is constant in batteries is the VOLTAGE. The resistance and current all depend on the circuit.
One battery does not have more amps than another, since amps depend on the circuit. Please, stop confusing people.
LastManAlive, your pistol started going faster because you added more potential difference to it. AAAA - D batteries all have a potential difference of 1.5V each, just with a different amount of capacitance.
1 Car battery = 12V, current in gun = 12/R
6 D Batteries = 9V, current in gun = 9/R
1 9V Battery = 9V, current in gun = 9/R
That being said, I do not recommend doing anything past 9v on this gun, you don't want the damage the circuits and motor. It will heat up and can eventually break much faster is a larger voltage is used.
eat shit! Any-who I really cant wait for this to come out, and [not sure if this has been said already] would it be possible to link the chains together at the ends?