A cold winter day. S&W Model 53 6" NIB with all accessories. I had three chambers loaded with .22 Jet ammo and three chambers loaded with .22LR (chamber inserts). I observed a target and wanted to test the trigger pull. Thinking that there was a .22LR under the firing chamber, I opened the vent window just enough for the muzzle to stick though. I fired and though the car had blown up as the chamber under the firing pin was a .22 Jet. I looked over at my hunting buddy and observed His mouth moving but no sound. Finally when My ears opened , he was saying "Please don't do that again". This was many years ago, yet he is still my buddy.