Why do so many people not use the solenoid by just hooking it up to a few 9v batteries? Is there an advantage to using the air gun modification? I am new to this and building one soon..

Thanks,
John

Hello Everyone! I have a few questions before I begin my first build which will be very soon hopefully. Not really the "first", years ago as a young boy, I built a "potato gun" but as it turned out, the police liked it more then I did, so they took it... Anyway, fast forward 20 years and here we are...