The Shiloh Sharps marked barrel leads me to believe that it is not a Green Mountain barrel.
I thought the same thing but the seller said that Mr. King stamped the barrel with the Shiloh-Sharps Model 1874 / CALIBRE 44 markings because he has the dies to do it. The seller also told me all the work was done around 18 months ago. I did not investigate any further.
