My understanding is that Teague only recently started lining 16 ga. barrels.... maybe that's the first set they did ?
That would be absolutely unacceptable tp me. If the people at Teague had measured OD as well as ID they would have surely discovered that the barrel walls were not thick enough to allow being bored to such an extent without coming through the barrel wall. Sure, the barrels have been proofed and are perfectly shootable, but moisture will eventually find its way under those bubbles and it won't take long at all for rust to come through..... IMHO