Not a squib, but don't know what to call it.
I was shooting at a range and fired a round that sounded and felt just like a squib. I was shooting a G17 and the slide wouldn't budge no matter how hard I pulled.
I was able to pull the slide lock with some difficulty and remove the slide from the frame. The barrel was still jammed and I couldn't remove it from the slide. I could see a gap about <1/16" between the case head and the breach face and the extractor claw had gouged the rim and was lodged about about half way into the edge of the case rim. I believe that this caused a lot of friction between the primer and the breach face preventing the barrel from unlocking from the slide.
I ended up putting the slide in a vice and using a dowel to drive the barrel down and it came away from the frame. The cartridge came out of the chamber and still had the bullet in the original position. I checked the extractor and firing pin. Everything looked fine so I reassembled the gun and kept shooting.
A few weeks later I posted about it and someone said that it sounded like a case with no flash hole and that he had heard that there had been several lately.
I had kept the round as a souvenir of sorts, so I put it in the bullet puller, knocked the round out and found that it had a powder charge, and also no flash hole as suggested.
I hope to never have anything like that happen with premium self defense rounds because if it had happened in that scenario the only backup would have been a second gun.
As far as squibs go, I inherited a Colt Model 1903 from my Dad. While cleaning it, I noticed a bulge in the barrel and asked him about it. He thought I did something to it, but I just noticed it when I got back from shooting it. Years later he told me about a time when he and a friend were shooting some old ammo out of it and and had a round where the bullet got stuck in the barrel. They didn't have anything to push it out with so my Dad was going to take it home to take care of it. His friend said, "I can get it out." He took the gun from him, loaded a round and fired it. It cleared the barrel and they kept on shooting it. I told him that was what bulged the barrel and they were lucky nothing worse happened. He didn't know much about firearms and only had the gun because it was found after his father died.
Lucky for me, US Armament re-released the Model 1903 in 2015 and new parts were available. I purchased some springs and a new barrel and it is good as new... at least for a 108 year old gun.
