Octagon.....not sure about your question. What I am referring to is a swamped barrel. We did what we called the "Golden Age Series" of barrels. They were done in four weights, and labeled as "A"..the lightest, B, C, and D, (the
heaviest).....they all had the same profile. The "A" went from .950 at the breech, down to .700 at the small part, and
.760 at the muzzle. The B weight was 1" at the breech, the C was 1 1/6" at the breech, and the D was 1 1/8" at the
breech. As they go up in size, all of the other measurements also go up by the same amount, with the D weight going
from a breech of 1.125 down to .875, up to .915 at the muzzle. Hope this answers your question.........Don