Easy to tell if it was the POS. stick a needle through a dowel at an angle so it will fit down the barrel. slide it down the barrel. at about that one inch breechward from the union, the pin will bump or catch on that lip like a bad corrosion pit, but it will be nearly all the way round. It has been a lot of years. IIRC the POS barrel was in the white and the better barrel was blued or blackened some how. As I recall on some of the guns it was possible to see a portion of a thread where the pieces met. I was not on duty when a police officer came in a few days afterward and had a receipt asking about the sale and gun. We had already heard about it on the radio but at that point did not know it had anything to do with what we sold, until the officer came in. Some of what I know is second hand, but I ended up taking the call when the importer, perhaps from Vermont, called and asked for our unsold units. I don't recall if I packed them up or assigned the packing job to one of the sales clerks. The similar looking but better guns had barrels that were one piece from end to end. But were turned on a lathe to look almost the same.
There was a similarly built Zouave reproduction that had a three piece barrel, but the tang, breech bolster and plug was a big single forged unit and had female threads. The barrel also had female threads and the two pieces were held together with a short piece that looked exactly like a one inch pipe nipple. The pipe nipple was only perhaps 1/16 or 3/32nds thick where the breech met the barrel. that was not much metal to hold all that pressure. I have seen other muzzle loaders that are truly scary, but not as bad as that POS.
as for whether the brothers used smokeless, that be irrelevant is the lip around the interior thread union creates a barrel obstruction. I have seen well made barrels that fail and split open just from a short started ball. I cringe when I hear these Bubba types brag about their 180 grains of Super Nuclear Whup Butt substitute powder under a 1200 grain Elephant skinner bullet Some poor idiot is going to put that load in one of those old Dixie wire twist barrel shot guns and lose more than fingers.
Sorry to rant on, but understand those guns violate a standard rule of safety with that internal lip. In some or many that lip might be smooth enough to never make a difference. Other than it might be a place for fouling to lay and start corroding the steel.
