Slip your finger into the trigger guard and hold it against the trigger. The revolver is loaded, cocked, and ready to fire. Keep your finger on the trigger. Now, with your left hand, take your index finger and run it across the end of the barrel, then poke the tip of your finger into the tip of the bore.
Some professional painters do it.
If you're one of them and still have all your digits, consider yourself fortunate. Your finger or hand might not have to be amputated, but because of the nature of an injection-type injury, there's a good change you'd lose the use of them. And it only has to happen once in all your years of spraying. Spray rigs, regardless of type, aren't inherently dangerous if used properly and with some common sense. Tim McNair, M.D., a board-certified emergency physician in Tacoma, WA, said that it depends on how you define serious.