What voltage should you run your liner tattoo gun?

You should run your machine between anywhere from 4 - 6 Volts, but there are other variables that come into play when it comes to the smooth running of your machine. You will want to of course make sure that your armature bar/rear spring is properly adjusted for lining, make sure that there is clean contact with your front spring to the contact screw and sand the front spring with a metal grade sandpaper if need be. It's better to have a digital power supply, as this will allow you to more precisely set the voltage of your machine.