I could only scan the video quickly, but I thought I saw full length round bar stock that was deep hole drilled and then button rifled. If drawing was done to lengthen the tube, was it to improve the barrel or manufacturing 'good enough'?
I suspect, if the round bar stock arrived drawn out in length, and it was used in that configuration, as opposed to cross cutting a 'plate' off, there was already some 'grain' alignment. A bit like the other penny example, or your dot thought, I'd think it would mitigate the defect of the 'dot' if it were imagined to be an inclusion, by diluting and distributing. If an inclusion started off as a random blob, wouldn't it take on the characteristics of an elongated 'seam' even if a seam wasn't intentionally used to create the tube?
My question would be, since there is an intentional lengthwise direction being created for 'firearms use', is this the best way to create a 'hoop'. There may be some thought that 'hoop strength' may be an attribute that resists forces that are ninety degrees to the length of the barrel.
On a side thought. If these 'dots' or defects present too much of an unknown. I wonder if the 'dots' could be 'stretched' or maybe drawn thin and elongated. Then, maybe a bunch of the questionable bars were twisted so that no single defect could present through and through. Then, this composed elongated bar were turned near ninety degrees to the long axis and wrapped as a tube. Only remaining thing needed would be cheap skilled forge welding skills and maybe a barrel could come out the other end.
If modern steel is so questionable, it's no wonder some thought had to be put into turning horse shoe nails into a gun barrel component. Then again, maybe modern steel doesn't have to be best quality to be 'good enough'. Just thoughts is all, CZ.
