ScottEdvin, to see some long-barreled rifles look at a few of the southern gentlemen in Walter Cline's book, The Muzzle-Loading Rifle Then and Now Either they are very, very short men or there are quite a few 4 or 5 foot long rifle barrels there.
My 16th birthday present from Dad was a 12 gauge English flint fowler with a 4-1/2 foot barrel. When Young & Immortal I used it a few times. It did carry just fine, but near impossible to swing it through the southern Delaware briars. This pleased at least one rabbit.
Now I am tempted by this screwy rifle at the Thomaston auction . . . guess I can't afford it . . .