That's how my turn at the Krag sounded yesterday. We also discovered the primers Cro is using have enough push to get the bullet into the throat, but not stuck particularly hard, when the powder fails to ignite for unknown reasons (thankfully a tap on a cleaning rod popped it out easily enough, and the gun was back to shooting in less than a minute.)
Thankfully for Cro (the owner of the rifle) and myself (shooter of said rifle,) this was a "best case scenario" for a squib load. Last round in the mag, and had it not been, we doubt another one would have fed into the chamber (that's how far the bullet didn't go.) Also, although the Krag is a "soft" shooting rifle, the round in question had zero recoil, and with earplugs in, all I heard was the "CLACK" of the striker hitting the primer. So, wait a couple beats in case of a hang-fire, open the bolt... and no bullet in the cartridge? And unburned powder pushed all the way to the front of the case? Huh. "Hey Cro, I'm sorry, but I seem to have lodged a bullet in your barrel."
We're not too sure what the issue was, theory is some oil from lubing the case made its way inside and dampened the powder, preventing it from igniting. The more important lesson, however, is when something weird happens when you're shooting, stop and evaluate the problem. It could save your rifle and your face.