I like to look at other people's brass sometimes when I go to the range, especially if I see something unique. Today I found a 9mm, it says "S&B" and extending from the open end, about halfway down to the primer end, there is a crack running. It goes all the way through as I can see light through most of it. Burn marks made by escaping gas run the length of it, so it wasn't made afterwards. I know it's not mine, because I only use Wally World Winchester at the range, but I am curious about what would cause this, and would it have been a misfire or other failure that the shooter would have noticed?