Is video shows a very serious and very dangerous example of why it’s important to know that your barrel is clear from obstruction. If something doesn’t sound right after you pull the trigger, you should immediately clear that firearm and check things out because chances are, something is wrong.
This girl is lucky she wasn’t injured, as are the other people in the immediate area. It seems that she experienced a squib load on the 2nd to last shot. While she cleared the casing from the rifle, she did not check for barrel obstruction. Once she pulled the trigger again, the newly-fired round ran right into the back of the previous round that didn’t have enough energy to make it out of the barrel.
The cause of a Squib is usually an under-powered cartridge, likely due to a missing powder charge, or a light powder charge. Many times if a cartridge is missing powder, the primer igniting is still enough to propel the bullet into the barrel, which in turn creates the obstruction. Then, if another round is fired, it will come in contact with this obstruction and cause some pretty dangerous situations.
The video below is a great example of a squib caught before it was too late. You’ll note in the video the different sound after the trigger is pulled.