The data IS consistant.
The top graph is pressure/time.
The others are pressure/distance.
"If the peak pressure is at .7 msec, and the shot leaves the barrel (?30") at 3.5 msec, the peak pressure would be 5-6" from the breech." - is an incorrect conclusion because the velocity isn't linear. You are accelerating something from a standing start.
The peak pressure is in the chamber, thus "chamber pressure" and it goes down as the expansion progresses.
The area under the curve gives the total energy transfer.
