Just obtained this barrel. It is a bit smaller than the one I reported on earlier here (and Fernando's example discussed here
http://www.vikingsword.com/vb/showth...ght=hand+canon).
The base is somewhat misshapen so it looks wider in the image. I do not think that this is a noisemaker.
142mm Long
46mm Diameter
23mm Bore
Again, from Portugal.
ETA. It also appears to have had the touchhole reenforced. Black powder resulted in significant erosion in these things.