I've seen this happen before, and I agree with track on his analysis.
The writing on the cases is what's throwing people off the issue.
The loader may have been trying to "fire form" used cases from a different rifle for the Fierce.
My assumption is, the reloader tried to bump back the shoulder after annealing, using a dirty resizing die, with plugged vent holes, is where the dents were created.
Then, he loaded up the cases with a fractional load in an effort to save the cases.
You're witnessing the results.
If there is a reason for such a fractional load, fill the empty air space above the powder with something like Dacron fiber or a similar filler that will be burned away, and the residue blown out the barrel.
I'm wondering if the person firing those rounds didn't have a bullet stuck in the barrel at some point????
He did manage to create a very nasty explosive condition within the chamber, rather than a controlled burn, loader beware.
