Some of the earliest 'cannon' were small-bore (inch or so) devices on the end of a pole. SOMEONE out there will remember the name of these - used in English battles about 1600 or 1700's (?).
I just finished making another golf-ball caliber mortar tube (4140) with round barrel and breach end done in an octagonal (just playing with it to see what it'd look like.
So now I think I'd like to do one of those OLD timey smoke poles - if anyone has the name of it, a design, or a URL leading to one.
Found this at
http://members.aol.com/BERLIER1/BPHIST.htmCANNON LOCK:
The first muzzle loaders were fired by simply shoving a slow match (fuse), hot coal, or red hot wire into a powder-filled flash hole (vent into the main chamber). The earliest surviving example is the "TANNENBURGER BUCHSE", dated prior to 1399. This is a simple tapered iron tube, formed at the breech end into a socket to accept a "PIKE-POLE" stock which was held under the shooter's arm (known as a "HAND-CANNON" OR "PETRONEL").