Actually TB, they weren't all receiving their barrels from Belgium. Krupp, of course, was German. I think Chromox was British. But even if they were, the blanks were bored in this country. That could make a significant difference, from one maker to the next. And it explains why, for example, that Fox offered 4 different barrel weights for each gauge gun they made. So obviously, they weren't all the same--even from the same manufacturer.
Larry you will be hard pressed to find a US made gun made between the big wars that have Krupp or English made barrels. Both countries lost most of their skilled workers in combat. Chromox was a Fox marketing name to highlight the fact that the barrels had a high chromium content, kind of like Winchesters "Nickle Steel". You really need to read McIntosh again on Fox barrel weights and why the were segregated in weight groups 1 through 4.
