I would be far more concerned with the condition of the metal including thickness in the first 14" to 16" from the breech as this is the area where they tend to let go. Even with thickness being acceptable you're still in a crap shoot IMO because you can't easily tell what lurks below the surface and this is particularly critical when it comes to damascus. You are essentially relying on the fact that the barrel forger didn't leave any large voids during manufacture that have been rusting internally for the past hundred years.
The barrel diagram and pressure curves provided above are a stark reminder that even 100 years ago the makers knew that condition and thickness in this area was critical.
Jim
