Problem solved!!!!!!

I found the cause of my bolt locking after dry firing after some head scratching. I finally traced the problem to a missing spring (one of two) in the trigger assembly.

Apparently at some time in the past someone disassembled the trigger assembly, and lost a spring. This prevented the front part of the trigger assembly from being forced back into position after firing.

I happened to have a spring that would work, so I replaced the lost one. Now everything is working as it was designed to.