Octagon barrel v.s. Round barrel

[George]

Early barrels were by necessity made round initially because they were forge welded around a mandrel their entire length after being formed in a "U" die from a flat scalp bar.

There were also other ways of making barrels which resulted in better barrels, but they were much more complicated and labor intensive. The English made 'twist' barrels by forging straight square rods of 1/2 x 1/4 inch or so and a couple feet long, then heating and bending those into a tube by spiraling them around a mandrel. They did that in sections, starting with thicker rods where the breech would be and ending with thiner at the muzzle. They usually used 4 of those and welded them into one when all were twisted properly.
The also took barrels made from one long skelp welded along the side over a mandrel and twisted them, literally, by fastening handles on them, then heating a section at a time and 'wringing' them the way you wring a wet cloth, ending up with a barrel in which the metal spiraled tightly from end to end.

The French made a thin barrel in the common way, welding a skelp along the edge, then layered on top of that metal which was spiraled around like English twist barrel. Once everything was in place, they heated and welded it all into one piece. The thin liner barrel was mostly removed in the process of boring and reaming.

I don't know if plain octagonal barrels were made this way, but the descriptions include octagon to round ones.

Spence

 

[M. De Land]

Thanks Spence for including that method which I'm also familiar with.
What I was trying to get at was that they were hammer forged around a mandrel with either process leaving them round until at some further point in their manufacture they were given the octagon shape by forging and filing.

 

[George]

Yes, I understood your point, and it's a good one. Didn't mean to step on it, it just seemed an appropriate place to point out that the plain tapered skelp wasn't the only way they were made. I think some people believe it was.

The whole business was a lot more complex and sophisticated than usually described.

Spence

 

[jd945043]

Guys you are forgetting that alot of "octagon barrels" were swamped. To. Make them lighter I guess

 

[Loyalist Dave]

Guys you are forgetting that alot of "octagon barrels" were swamped. To. Make them lighter I guess

well IF you get a chance to look at some original swamped barrels, the degree of the "swamping" is much less than we use in our repro barrels today, in many many cases. So there is a debate over was it "intentional" or was it merely a less then perfect filing/grinding of the barrel blank? The natural tendency when a person files something long like a barrel is to remove less material at the ends than the middle. One has to know certain techniques for getting an even filing for the full length.

LD

 

[Uncle Miltie]

I believe oct to rd is just purely aesthetics. I don't ever recall seeing an oct to rd barrel on a muzzle loader but the ones I have seen on the single shot falling block BP cartridge rifles makes a truly sharp looking rifle imo.

NY state makers were fond of using octagon/round barrels.

 

[tenngun]

It's actually much simpler, because of style...

Rifles were being made in the Germanic countries by the mid 1550s, the Germanic gunsmiths are the ones who brought their rifle making skills here...

They preferred the styling of an octagon barrel...

Well back to the early sixteenth century square barrels were made. And Henry the eighth had a pentagonal barrel made on a rifle. It was sans sights, the point of the pentagon on the top was a sight.
I tend to agree, tge eight sides were practical for multi sided four works and is even, eight works, and the next would be sixteen. All other multi faceted will produce odd corners or an extra angle.
It’s notable that rather few military eighteenth century guns were made with whole or part octagon, but almost all civilians were were at-least part octagon.

 

[smoothshooter]

Guys you are forgetting that alot of "octagon barrels" were swamped. To. Make them lighter I guess

Inletting a swamped barrel must be a pure nightmare, at least until you have done 15 or 20 of them.

 

[smoothshooter]

well IF you get a chance to look at some original swamped barrels, the degree of the "swamping" is much less than we use in our repro barrels today, in many many cases. So there is a debate over was it "intentional" or was it merely a less then perfect filing/grinding of the barrel blank? The natural tendency when a person files something long like a barrel is to remove less material at the ends than the middle. One has to know certain techniques for getting an even filing for the full length.

LD

It may have been by design.
The less a barrel is swamped, the easier it is to inlet it into the stock.

 

[billraby]

Inletting a swamped barrel must be a pure nightmare, at least until you have done 15 or 20 of them.

Inletting a swamped barrel is no harder than a straight one. Even for the first time.

 

[dave_person]

AND...why the octagon to round barrel? :haha:

LD

Hi,
Dave,
That's the Spanish and Portuguese for you. The octagon section provided most of the strength of a round barrel with the same diameter corner to corner but shed a lot of weight. So the Spanish used the octagon section to provide the strength at the breech and then turned most of the barrel round and very thinned walled to keep it very light toward the muzzle. The transition also gave them a convenient spot for beautiful decoration. Octagon barrels were often referred to as "square" barrels because the gauges used to check their dimensions were simple squares cut from a flat metal bar. You simply checked the octagon barrel by placing the square against 2 flats, and then turn the barrel 45 degrees and check the next pair of flats and so on.

dave