Apparently some confusion as to what I was looking at.

It should be something like this:

 

@Danko Yes that clearly shows something happens @ ~320Ω. I'm tempted to go back and reproduce my circuit and take smaller incremental measurements from 200-400Ω and around 600Ω but your simulation graph also clearly shows it around 320Ω. What happened? The other aberration @ ~600Ω in my experimental data is also curious. I have not studied the Eber-Molls or other such models. Do they come into play here?

 

Yes that clearly shows something happens @ ~320Ω. I'm tempted to go back and reproduce my circuit and take smaller incremental measurements from 200-400Ω and around 600Ω but your simulation graph also clearly shows it around 320Ω. What happened?

@ 320Ω transistor becomes fully ON (saturated, shorted) and works as piece of wire.
After 320Ω overall resistance is almost equal to resistance of R1, because resistance of C - E is close to zero.

The other aberration @ ~600Ω in my experimental data is also curious.

Something wrong with measurements... I think your next measurements will much more accurate.
Simple simultaneously measure voltage C - E and current of R1, as shown in post #18.

I have not studied the Eber-Molls or other such models. Do they come into play here?

Circuit simulated in LTspice, about used models you can read here: http://ltwiki.org/index.php?title=Q_Bipolar_transistor

 

@ 320Ω transistor becomes fully ON (saturated, shorted) and works as piece of wire.

Aha! Got it, thanks Danko. Still a very minor resistance in addition to Rc but nearly zero. Yes, I was a bit suspicious of the higher reading and if it had been the only one would have assumed it was just a "flyer" and ignored it. Thanks again!
Sam