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.
SAAMI did not come along until the mid-1920's either. But once they did, the pressure standards they established were different for guns with short chambers vs long.
Joe, you must not have read the famous story about John Olin having something like a couple thousand proof loads fed to a Win 21 without harm. American manufacturers went through essentially the same proof procedures as the Europeans. The only difference was, the standards were overseen by SAAMI which was an industry organization, rather than a govt entity running the proofhouses like in Europe. You'll find a VP on 21's, standing for "violent proof"; an HP on Elsies, standing for "Hunter Proof", etc.
And your nonsense about the NID being a "cheap made gun" . . . have you been into the controlled substances again, Joe? The NID and Elsie Field Grades and the Fox Sterlingworth all cost virtually the same. Plenty of NID's still shooting, 80 years later. And guess what company John Olin went to with a request to build a double for his 3 1/2" 10ga shell? He didn't do it with his own Model 21, but rather asked Lou Smith at Ithaca to do it with the NID.
