Octagon-to-Round Transition Step

[silky]

On a new octagon-to-round barrel, without bands, there is a small step from the flats to the round portion even at the centerline of each flat.  Is it standard practice to draw file the flats such that the step disappears?  Since there is so much "it depends" with respect to old guns, please consider the context of the question a mid-18th Century New England-made fowler/musket.  The pic attached is not to scale but illustrates what I'm talking about.

I searched and the only definitive answer seems to be that a big step is unsightly, and the few pictures I've found are inconclusive.

- Tom


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[rich pierce]

They are made that way today, with the step and a high ring. All originals I’ve seen are much more subtle. Most builders use todays barrels as they come from the maker.

[smart dog]

Hi,
Many New England guns used French or French styled barrels.  These often have a short octagon sections and then a gradual transition to round with little or no step or wedding band.  Here is an example copying the French barrel on the famous Hawk New England fowler.  In this case, I also had to cut the sighting plane all the way to the front sight. 





dave

[Bob Roller]

That picture shows a good looking idea. It is easy to change the angle of the lathe to a less radical shoulder.
Bob Roller

[silky]

Hi,
Many New England guns used French or French styled barrels.  These often have a short octagon sections and then a gradual transition to round with little or no step or wedding band.  Here is an example copying the French barrel on the famous Hawk New England fowler.  In this case, I also had to cut the sighting plane all the way to the front sight. 





dave

Thanks for the pic, Dave -- that helps a ton.  With respect to the transition on those flats, was it as simple as draw filing the entire flat forward until the depth finally extended into the round barrel that small distance?  I really like that seamless transition and plan to do the same on mine. Any tips or techniques you can share are appreciated.

- Tom

[Dphariss]

Big steps are stress risers. You don’t want these. Especially if the barrel is cold rolled steel. Also this should be done before final reaming of the bore.

[A.Merrill]

 I have never built a rifle with a octagon to round barrel for one reason, the step down looks terrible to me.   Al

[smart dog]

Hi Allen.
They are quite beautiful when the octagon section is tapered and there is a nice sculpted wedding band at the transition.  What is ugly are those barrels that just have an abrupt step down and those are not particularly historically accurate.  The better octagon to round barrels made today are roughly of Spanish form and proportions.  Here is a real Spanish barrel made between 1690 and 1713 by one of the greatest barrel makers of all time.









dave

[A.Merrill]

The only octagon to round barrel I can think of off the top of my head I liked is the Henry Albright, in Thoughts of the Kentucky Rifle. The octagon section goes past the rear thimble and fades into the wedding band, best I can tell from the picture.    Al

[Daryl]

That's an especially nice transition with the engraving and carving.

[Pukka Bundook]

Dave,
Sometime, it would be nice if you could show us how you did the barrel with the full length sighting plane.
Very nice work!

[flatsguide]

I’ll second Richards (Pukka) comment, very fine work indeed.
Cheers Richard

[silky]

Spent some time tonight with the files and knocked down that unsightly step... I think it looks much better now (there's still some final clean-up work and polishing to do but that will be at the end of the build).  I decided not to out-do those Spanish barrels this time around

Thanks for the help!

- Tom

[A.Merrill]

Silky, now that looks good  and I would use it.   Al

[silky]

Silky, now that looks good  and I would use it.   Al

Haha, thanks, Al!  I agree -- the ones with abrupt, sharp (lack of) transitions are not easy on the eyes.

- Tom

[rick landes]

I had recently seen a transition done over several inches of the barrel where the mated flats slowly triangulated to an isosceles point and became round. I have no idea how "HC" that is but it was a soft transition.

[Pukka Bundook]

Rick,
We see quite often where the octagonal section turns to 16 sided for a few inches before the round beguis. This really smooths out the appearance too.

[Daryl]

8 to 16 on an 11 bore capper.