I am mystified by the description. The extreme curvature of the butt stock leads me to believe that perhaps it may have been a cut down hunting rifle, making it more user friendly on horseback. (Indians were notorious for doing this with long barrel guns, & it made a lot of sense). Again, unless someone can correct me, I cannot think of a manufactured carbine with such a butt stock & w/a hex barrel. The South was hard pressed to arm their soldiers, so a lot of men provided their own arms & a cut down hunting rifle is not out of the realm of possibility. I checked out the Cabela's version of the cut down Hawkens & if your remembrance is of a similar description, I would venture a guess that it was a cut down hunting rifle. Without seeing the weapon, a guess is all I can give.