Those look like some of those unfinished Belgian shotgun barrels Turner Kirkland imported about 25 or 30 years ago. Man oh man, I bought a pile of those unfinished barrels. I wanted the ones that were still singles, before they were mated into doubles. They made great short trade guns, and horse pistols. You really had to watch them though, there were many gauges that were not common to the U.S., and occasionally you would get one that wasn't finish reamed inside. Some of those barrels had proofs on them and some did not, So I always proofed the barrel before I built the gun. I still have a few orphans from that purchase floating around in the shop. I think they were three for ten dollars, you had to buy them three at a time, and there was no guarantee of gauge, or barrel length. They are good strong barrels, even though they look light.
Hungry Horse