Fowler bore question

[SyLibby]

My buddy has a TVM fowler. I dropped my camera down the bore to check the breech face today. I noticed that there was a distinct ridge inside the barrel at the transition from octagon to round.  It's this normal?

[Stophel]

Well, it certainly shouldn't be!

[Pukka Bundook]

No, Very Abnormal, Sy.

[rich pierce]

Run a tight patch and see if you can feel it. This is something I’ve not heard of before. If bulged I’d not use it.

[Eric Krewson]

I thought I had the same on my Gustomsky trade gun, turns out it was a reflection off the breechplug, I was sure my barrel was ringed.

[SyLibby]

Thanks all. I'll run a tight psycht and see if I can feel it. Seemed odd

[Daryl]

I thought I had the same on my Gustomsky trade gun, turns out it was a reflection off the breechplug, I was sure my barrel was ringed.

Good point, Eric. If it is at the wedding band, a ring would be difficult to see on the outside, but you can always feel them on the inside.

[Pukka Bundook]

Again good point Eric!
We can often see multiple rings in a smooth -bore, especially old one that were not bored a true cylinder, but of  the friction and relief  type.

[Daryl]

Hall Sharon's deep groove button barrels of the 70's had rings one end to the other, due to "friction/pressure buildup then relief". They were hard on the eyes to look
through at a light bulb.  The .36 I had did shoot quite well with denim patched .375's, though. Those turned into little rounded bottom, flat topped slugs
when seated.  They were not difficult loading, with the gun's 5/16" steel rod. The .350's did not shoot well. I assume the slug obturated due to their increased friction,
 while the short contact round balls did not obturate.

[Ric Carter]

Again good point Eric!
We can often see multiple rings in a smooth -bore, especially old one that were not bored a true cylinder, but of  the friction and relief  type.

That is how you check a barrel for being straight, rifled or smooth bore. They of course are harder to see in a rifled barrel until you get your eye trained for it. The rings are light bars, and there are around 100,000 per inch, and they only come into visible spectrum where the rings show. If they aren't all perfectly concentric, your barrel isn't straight. I inspected barrels for several major manufacturers, and could tell them where the barrel would shoot if they were off.

[Stophel]

Cutting the "wedding band" shouldn't have pressed the bore in to make a ring inside... surely not.  Maybe it just has a "jump" in it that just happens to line up about where the band is....

It may not be enough to matter.  If it is, maybe you can hone it out with a shotgun bore hone.