Why swamped barrels?

[LME]

If you are a Machinist you are aware that any long turning without center support will be swamped after turning newbies make this mistake usually once in their learning stage. I wonder if swamped barrels were a mistake? I can see no good in swamping a barrel. Mass dampens harmonics and what little weigh loss one gets from swamping a barrel is minor? If there is a benifit in swamping a barrel I haven't seen it yet.

 

[Art Caputo]

I think the swamped barrel attributes of balance, weight, breach/muzzle strength, sight position and visual appeal well account for its use. Given the vast majority of practical muzzleloader configurations, I seriously doubt barrel harmonics was a rationale, particularly when used with a patched pound ball, While barrel harmonics is a viable consideration with modern precision rifles its measurement and management with a muzzleloader would be lost in the all the other variables that influence accuracy. I surely wouldn’t make my decision to use a swamped barrel with a “conventional” muzzleloader solely based upon improved barrel harmonics. IMO.

 

[Patch]

Lots of great comments in this thread so far, I enjoyed reading them and learned a lot from everyone!

Here is a video of Wallace Gusler making a barrel the traditional way. At around 2:54 right near the beginning he says something like: when welding a barrel you start in the middle and work your way to the ends. Now this would draw the metal out and create that swamped pattern, so was swamping the result of how it was made and they worked around that or did they work around the making process to achieve the swamp? Could they have welded it up differently to make the barrel straight?



It seems like to me that it came out swamped, it worked, so lets dress it up and put it in a rifle? And that making it straight would have used additional metal before forging (a major consideration considering its value at the time) and additional file work after forging (another cost consideration)?

 

[Coot]

Lots of great comments in this thread so far, I enjoyed reading them and learned a lot from everyone!

Here is a video of Wallace Gusler making a barrel the traditional way. At around 2:54 right near the beginning he says something like: when welding a barrel you start in the middle and work your way to the ends. Now this would draw the metal out and create that swamped pattern, so was swamping the result of how it was made and they worked around that or did they work around the making process to achieve the swamp? Could they have welded it up differently to make the barrel straight?



It seems like to me that it came out swamped, it worked, so lets dress it up and put it in a rifle? And that making it straight would have used additional metal before forging (a major consideration considering its value at the time) and additional file work after forging (another cost consideration)?

Not to mention but draw filing would also tend to work the mid section more than the ends. I think that when making a barrel by hand, that swamping would almost be a natural by product of the process. The fact that swamping helped looks, weight & balance in a long barrel meant that there was no reason to try to make them straight. Shorter, straight barrels came into vogue when most barrels were made in factories using machines where straight was easier to make than slightly curved. Better metals and shorter lengths negated much of the reasons for swamping.

 

[Crow-Feather]

I've been considering building a kit and need an answer to a question. I never heard the term "swamped" applied to a rifle barrel until I started reading the term on this forum. What is swamping and why were barrels swamped? Thanks

A gunsmith screwed up and started a fad.

 

[Grenadier1758]

Just like @Patch and @Coot observed and Wallace Gussler pointed out as he forge welded a barrel.

When you forge weld a barrel, you start in the middle and work toward the ends. Under the intense heat of the welding process, metal moves away from the middle of the barrel and the result is a thicker breech and thicker muzzle. Basically, swamping happens when you forge weld a barrel. Sometimes its more of a swamp and sometimes less, but that moving of metal can't be avoided. Fortunately the result was an accurate shooting barrel. It was less labor to inlet a swamped barrel than the labor to take a swamped battel and file it straight.

Swamping happened and it worked. Serendipitous manufacture not engineering in this case.

 

[olskool]

i have a 40cal NC mountain rifle with a straight barrel. but it is 3/4 cross the flats at 42in. it balances real good, right at the entry thimble. i would like to have the same setup with a 38in barrel, that should be perfect,,,,,,,,,,,,

 

[SOLANCO]

Stress from internal gas pressure will be higher at the muzzle. That is why o-l-d cannon barrel were larger just at the muzzle. It was not for pretty. Ask a good mechanical engineer - I understand it but my explanation would be long and unclear.

Look at Zonie's explanation but, (with respect, Z) don't consider the weld strength. It is a matter of mechanics/geometry.

I don't know if this was an original design consideration, but the ring around a cannon muzzle makes the barrel much easier to move. Rig ropes behind the ring and around the ball at the rear. Especially true of naval cannon with masts and spars providing plenty of purchase for a hoist. Examples in Patrick OBrians books.

 

[oldwood]

Olskool..........I to have a W.Va. Monongahela River rifle in .40 cal. X 3/4" X 38". Walnut stock , greased patch hole , rt. side of butt stock. Copper thimbles with repurposed original iron b/p , trig. guard from Pittsburgh school. She's ugly , but shoots a ball true as any and carries like a dream. She's my favorite for woods loping companion. .........oldwood

 

[George]

It seems that whenever the subject of forging barrels comes up it is assumed there is only one way it was done in the day. That is, form a long, slender piece of metal, thicker on one end and tapered. This is heated by small sections and progressively bent and welded into a long tube, with a seam the full length on one side. It's true that was done, but there are other more complex ways. One British and Spanish method was to form straight rods of metal about 2 feet long, 1/2" wide and of different thicknesses. These were heated and forged in a spiral fashion around a properly sized mandrel and welded into one piece. About four of these were made, of appropriate thickness depending on where it was in the barrel. Then all four were welded together successively to form a tube. From there the reaming, shaping, filing, turning on the lathe or whatever were basically the same as with the tube made of a single piece of iron. The British called these twisted barrels, the Spanish called them wrapped barrels. The single piece barrels were called common barrels. These twisted barrels were of a much higher quality than the common ones.

It would seem that many of the suggested reasons for swamped barrels being made that way would be precluded by these methods of making them. I've read a lot about how barrels were made in the day, British, Spanish and Portuguese, and I'm of the opinion they made them exactly as they intended, accidental swamping wasn't a thing. In the 1718 Portuguese book The Perfect Gun the actual dimensions of barrels are given, and they were swamped. On purpose.

Spence

 

[Patch]

but there are other more complex ways...twisted barrels...

That sounds like you would need a lot of infrastructure and a lot of skilled labor to achieve? At the very least it sounds much more time consuming? For a typical 18th century gun maker in America, would it be as easy to make a straight barrel as a swamped barrel? And if so, how would they do it?

I know typical is a difficult thing to define here and many parts were imported, but any help understanding the matter would be appreciated.

 

[Col. Batguano]

Let's think about the physics of what happens with the pressure wave in a barrel. When a sealed container (of constant strength) blows up it usually blows up in the middle, not the ends. That's because the pressure wave bounces off both ends and when the waves converge their amplitude is doubled. The precise point is the first to yield, and then it "rips" backwards (due to the proximity of other similar amplitude waves) and, the lack of support from adjoining material.

In an open ended tube those same forces apply, but pressure is decreasing (due to the expanding volume for the gas) the further down the tube the projectile is traveling. If a muzzle is obstructed, the force is concentrated when the projectile meets the obstruction, and the gas seeking to exit has its' momentum concentrated where the projectile was stopped, and the pressure spikes at the point of the obstruction. [As a case in point, that's the (cartoon reason) why Bugs Bunny was able to blow up Elmer Fudd's shotgun with his finger so effectively, and why it peeled back at the muzzle.]

Zonie should be able to give us the metallurgical technical data of yield points of supported and unsupported metal much better than I am able to. But apart from style, there IS a real and fundamental reason those older cannons had muzzle ring reinforcement; they NEEDED it.

 

[Stophel]

For a typical 18th century gun maker in America, would it be as easy to make a straight barrel as a swamped barrel? And if so, how would they do it?

But, WHY would they do it? Straight rifle barrels are HEAVY, clunky, weight-forward, unbalanced, awkward lumps of iron. Gunsmiths/barrelsmiths knew what they were doing. They trained for years. They could make whatever they wanted with no problem.

Really straight-ish rifle barrels seem to have come along in the early 19th century, as rifle barrel making began to be more mechanized, with big grinder wheels grinding the flats. I have a ca 1820 rifle from Massachusetts. About .58 caliber, the barrel is, as I recall, about 41" long and pretty close to 15/16" and "straight" (more or less). It's fairly hefty, and it's way out front. Definitely lacks the finesse of an earlier gun with a tapered and flared barrel. Both in handling and in style.

 

[Patch]

But, WHY would they do it? Straight rifle barrels are HEAVY, clunky, weight-forward, unbalanced, awkward lumps of iron. Gunsmiths/barrelsmiths knew what they were doing. They trained for years. They could make whatever they wanted with no problem.

I think that's an unfair characterization of straight barrels but I don't want to get pedantic, so sure, swamped barrels tend to handle better and are lighter. But it seems like that's more of a modern priority: making something that's lighter in the woods and something more commonly identified as an earlier rifle feature. If you look at it back then, the trend in barrels generally evolved to get shorter, straighter, and smaller caliber. Many smaller caliber barrels had very thick walls with the idea being it has plenty of room to grow, get its rifling freshened or get rebored and rifled to a larger caliber. Swamped barrels not as much. People depended on their rifles way more back then and the metals were less advanced than what we have right now so it would seem like the advantages of a straight barrel (more accurate and longer lifespan) was the driving force and manufacturing reflected that instead of the other way around? Mechanization would have adapted to facilitate swamping if nobody was purchasing straight barreled rifles.

But the crux of this discussion is why were early American barrels commonly swamped? And I'm not an expert, just trying to learn of few things in the process. But so far we have one demonstration of traditional barrel making that achieves a swamp naturally, and one explanation of a very complicated and time consuming process for making twisted barrels. It appears as if the answer to that question is because it worked and it was easier. But any explanation of early barrel making processes other than the two already mentioned would help to shed some light on the discussion.

 

[Stophel]

I think that the people who ask "why not straight barrels?" simply do not understand rifle architecture and design.

 

[George]

It has always been fascinating to me to read accounts of the manufacture of barrels in the 18th century. Here's a link to one which gives a lot of detail about several methods. It's "An Essay On Shooting" by Wm. Cleator, about 1790. The part of interest is the first three chapters, The forging of barrels, Boring and dressing of barrels, Improvements in the manufacture of barrels. It's Google Books, can be a bit flakey to manage, but find Chapter #1 and use the < > in the lower right to turn the pages.

It's only 30 short pages. Try it, you'll like it.

https://play.google.com/books/reade...ontcover&source=gbs_atb_hover&pg=GBS.PA11-IA2
Spence

 

[Patch]

Who cares about architecture and design when they could make whatever they wanted with no problem?

 

[Stophel]

If the question is "why swamped?" the answers have been given. Mechanically speaking, it allows for a large breech to help withstand pressure, most important with forge welded soft iron barrels. It takes a lot of weight off, since you don't need that full thickness of the barrel all the way up, just at the breech. And the flare at the muzzle brings the front sight more in line with where it should be.

Aesthetically, it looks good. They carry and balance well (relatively speaking). The flare at the breech provides for flare in the lock panels and a wider wrist, and stock shaping that really isn't possible with a straight barrel.

I know a lot of people today really want to try to make an "early" or "pre-Revolutionary" rifle with a cheap straight rifle barrel, but it really don't work that great.

 

[George]

The way swamped barrels were made in the period was much more subtle than many barrels we see today. I have an original 28-gauge smooth rifle with a hammer-forged octagonal barrel 49 1/8-inches long that is swamped, but you can hardly tell it. It just looks tapered, and I never realized it was swamped until I carefully measured it years after I got it.

The breech is 1.1", it tapers down to about 3/4" (.765) at 15" from the muzzle, then expands to 7/8" (.875) at the muzzle. This next photo covers the entire area of expansion, but you have difficulty seeing it even if you know about it and sight along the top flat.

The rifle weighs 6 lb. 15 oz., and in spite of the very long barrel it balances very well, right where you need it.

One thing I think I've learned after quite a few years of reading how the old boys built their guns is that many of them had a deep understanding of what makes a gun fit and handle well, they knew how to make them that way, and they insisted on it. Swamped barrels were not the only subtle thing about the guns they built.

Many guns with swamped barrels sold today lack that subtlety, the swamping jumps out at you, and if exaggerated enough, makes an ugly gun.

Spence

 

[Cap'n Ball]

Balance. Balance. Balance. My first flintlock was a full stocked 42 inch barrel. It was very front heavy which made it hard to hold steady through the whole pffft bang time. I only rarely shot it at all and it became a parade gun. I later saw a used hand built flinter, also 42 inch with a full stock, bur with a swamped barrel at a price I could not afford. The seller said to try a few shots anyway. With the swamped barrel the center of balance was directly above my left hand and the group was as good as I ever can shoot. I told him I would take it and my wonderful wife helped me to afford it. I would not sell it for double what I paid nor would I purchase a barrel over about 32 inches that was not swamped.