44 AMP,
I believe the primer was intact.
As I said, there was no bang, explosion, or flame and nothing to indicate there was a problem.
I have a theory. First, let me lay a little ground work. A diesel engine does not have spark plugs. The explosion is created by the piston placing the fuel mixture under pressure. The higher pressure creates heat. I believe the same thing happens when the firing pin or striker hits a primer. The anvil plays a role in this.
So, my theory is, the bullet could have been dislodged from the case during one of the three or four blows and I did not know it was free. Thinking the bullet was still seated in the case, I gave an extra un-needed blow. Perhaps when I raised the puller for the final blow, the bullet was resting near the case then when I hit the concrete, the bullet was able to travel fast enough to create enough pressure/heat on the powder at the bottom of the puller.
I apologize fore the layman's version of this but I'm not an engineer and I don't play one on television.