I made this one to have a 16 sided section. Unfortunately, I don't have a photo showing this section very well.[url]
http://photobucket.com/albums...locks/?action=view¤t=fowlinggunweb4.jpg[/url]
here's one I did a couple of years ago with a short 16-sided section.[url]
http://photobucket.com/albums...cks/?action=view¤t=7119170-R1-013-5.jpg[/url]
It's not particular to any style of gun. I've seen English barrels done this way, French barrels, German barrels, Spanish barrels....with or without a "wedding band".