Probably more than you want to know here
https://sites.google.com/a/damascusk...e.com/www/home
Parker briefly fabricated Laminated Steel tubes in house. Scroll to the bottom here
https://docs.google.com/document/d/1...o/edit?tab=t.0
With a full size high resolution close up of about 8" of barrel, where the contrast is most apparent, we could confirm the composition of your barrels.
re: safety of using pattern welded barrels see
https://docs.google.com/document/d/1...A/edit?tab=t.0
Almost all the U.S. makers sourced their "rough forged tubes" from Birmingham (early on) and primarily from Belgium, but there was no relationship between H&A in Norwich, Connecticut and Parker Bros.
BTW: H&A stated that their "Stubbs Twist" barrels were "Guaranteed for use with Nitro Powder"
