Thanks for all of the ideas..... I sat around looking at disassembled pictures for an hour or so and came to the conclusion that there was absolutely no way that I could have missed the barrel lug slot with the pin... my biggest fear. I was also confident that the recoil spring was properly assembled so........
I wrapped the grip with leather and put it in my larger vice and started applying a little more pressure. No luck. The slide still only came back less than 0.25 inches and the barrel hood still only dropped about .030 inches from full lockup. I started pulling back with quite a bit of force while trying to push down on the barrel hood with my thumb.... still no luck. I kept the pressure up trying to pull the slide back and lightly tapped the barrel hood with a small rubber capped hammer...... SUCCESS!! The slide retracted! I blocked it open and then removed the slide before ever letting it close again.
Examination of the disassembled gun did not show any anomolies in the components. The recoil spring assembly was properly assembled. The only thing unusual was a small white plastic fragment 0.034" thick, 0.090" wide, and 0.108" long that was near the assembly pin hole in the barrel lug. I re-lubed and then reassembled everything.... all is normal now.
The only thing I can figure is that the plastic fragment I found had somehow actually got into the barrel lug pin hole below the assembly pin and would not allow the barrel to swing down completly out of battery until I drove it down with the hammer. I have no idea where the plastic came from.... it doesn't look like anything I used today... not even oil bottle tips, etc.... I guess it could be "holster lint" that somehow invaded... I just don't know.
In any event everything seems to be OK now. Thanks for all of your ideas and thoughts.... THEY REALLY DID HELP!
Cheers,
Don