Squib is a strange word for a bullet stuck in the barrel of a gun. Recently, I had one of my own to deal with in a .38 caliber revolver I was shooting. This is how I cleared it from the barrel.
If you deal with this type of PVC valve in your plumbing, then you need to make a Valve Tamer. This is a simple project born out of frustration with hard-to-turn PVC valves.