Thank you. That makes far more sense than anything the OP who has been involved with this thing for 10 years has said here or anywhere else.
With that explanation, I can see a 60% fault to T/C, and 40% to the OP for loading WELL over book maximum and basically creating a bomb that exacerbated the headspace issue to a catastrophic level.
Except Selmer's example is the opposite headspace issue the OP claims to have had...
Well, there goes that. Selmer's explanation has still made far more sense than anything the OP has said to date.
Selmer's explanation is perfectly legitimate, just for the opposite problem which he illustrated quite well. OP says he had excessive headspace which caused escaping (?) pressure to somehow unlock the gun. More likely scenario is his overloaded round flexed the action enough to unlock it... Selmer's wasn't ever in battery to begin with because the lugs didn't fully engage...
