I haven't seen any info to the contrary and invite any and all info from this side of the pond on tube sourcing, but pre-WWI, almost all accounts give that all(I'm sure there are exceptions) American double makers less Remington & Winchester, sourced their tubes abroad "in the rough". That is why they fought so hard to keep the "single tubes bored in the rough state" on the free list. And every time there was a potential tariff there was a huge amount of wailing & gnashing of teeth which entailed a letter to the tariff folks. Post WWI, that was a totally different story as the American makers had to look at home for sourcing because the sourcing connections/routes were non-existant.
A few accounts give that Krupp tubes were acquired at the facility in Essen but I do not think that to be the case as Krupp only made big guns and not small arms. To my limited knowledge Krupp did not "rough bore" any tubes for smallarms.
Kind Regards,
Raimey
rse
