Cut down guns... from the Pontiac's War to Alexander Henry (Younger) on Red River, there are mentions of cut down trade guns. Even more common are mentions of burst barrels... and the Henry quote says he was hunting with a gun that was cut down after it had burst. We also know that they didn't have hacksaws.
They did have files, and there is lots of stuff that was cut (like all that re-worked trade silver), plus somebody posted on another site some broken axes that had marks like they were being used as anvils for cutting with chisels.
The cut marks are soooo obvious on your barrel that it is a noteworthy piece that could be a example of what we see in the quotes. It doesn't surprise me that it was bent to finish the cut... I do that myself with metal.
Avatar... actually stole the pic from the Brit detecting forum... it has my last name on it.
Great finds Mnlineman. I too had a great first day out about 2 weeks ago. Pics coming soon as the camera battery has to be charged, but to give you a preview....... nice button, copper fish hook, and a 1784 half reale. Watch for it. It would be a shame to let the fur trade forum die.