Don,
The only concern I have is that the alloys are unidentified. I ended up chasing cracks. I wondered if the alloy used for the barrels was "unweldable" alloy that contained lead (Pb) to make it more machineable, as is common in machined parts that won't get welded. It could have also been that it had high sulphur and not enough manganese to offset the sulphur negative effect on welding (cracking).