Quote Originally Posted by Peter Laidlericon View Post
It is a Mk2 barrel and the piece you see in pic 4 is a sleeve shrunk onto the rolled Accles and Pollock barrel. These barrels were obsolete in 1952(? earliest mention that I can see). They were made by rolling the rifling in a lengths, and shrinking the nocks form on. There weren't any failures as such but the barrel part would work loose in the nocks form and pull away slightly. When this happened you could usually see where the positioning pin was loose too. Because the rifling in these barrels was not machine cut but rolled over a former the rifling always looked half finished and the bores were never as bright either. I only ever saw a few in service as they'd all been culled early on. The irony is that I did see a couple in NZicon though! BAR and Baal were pretty close......
If anyone in Canadaicon finds an A&P fabricated barrel, please let me know so that I can at least offer to purchase it...

After re-examining the 4th,5th and 7th photos, I believe that this is actually a Long Branch 2 groove barrel...the '42 date and the poorly struck marking beside it are typical of an early Long Branch barrel.

The mark referred appears to be the change in machining from a concave? taper from the knox form to a straight taper for the barrel.