I was shooting a 9mm pistol the other day and had a failure to fire. The primer didn't fire and I immediately went into a malfunction drill. The next round would not chamber and I stopped to see what the problem was. The bullet (a factory 115gr FMJ) was stuck in the throat but not engraved with the rifling. A very slight tap knocked it out of the barrel. I lost the casing in the high grass while clearing the pistol but there was NO unburned powder present in the pistol.
The only explanation I can come up with is a casing with NO powder and either a dead primer or no primer. (I never found the casing) It wasn't a squib load because nothing fired and the bullet didn't travel down the barrel past the throat.
There's a strong probability that it was an old factory loaded cartridge but I can't be certain. I had dumped some Winchester white box rounds on top of a large box of my reloads. The failure occurred on the second magazine loaded from that box.
If it was one of my rounds that I had loaded - it was a triple failure of: bad or no primer, no powder and poor crimp. Not saying that's impossible but I've had very few bad rounds over my lifetime of reloading.
I'm still not certain what happened.