"Swamping" a straight barrel

[Mountain Rifle]

In studying pictures of original long rifles, it seems that many of them had only the slightest taper and flair in their barrels. Could that be achieved by draw filing a straight barrel? It would make a stock blank easier to inlet. I'm not yet ready to build, but I am curious. I would like to hear from experienced builders. Thanks.

MR

[Stophel]

I once had the idea of "swamping" a straight barrel.  I gave up that idea pretty quickly.   

[Rich]

I did a pistol barrel. Turned out but more work than it was worth. A farriers rasp was used for the rough work.

[kaintuck]

Yes, you can do it.....good files are the base, and lots of elbow grease......think in terms of hours of filing, like one hour per flat. It's like anything in this hobby...we start with the raw product, and work until it's done the way we desire.
Good challenge!
But it IS like eating elephant......one bite at a time!

Marc n tomtom

[smallpatch]

Two quick questions.
Why would you want to do that?  Seems like an awful lot of work.

Second, how would it make it easier to inlet?

[smart dog]

Hi MR,
I have done this a few times now.  It is a lot of work.  I used calipers, files, and a floor mounted edge sander with 8" belt.  My procedure was that I determined how much to take off each flat at 6" intervals along the barrel to match my planned profile.  I then filed the flats at each of those spots to the correct dimensions determined with my caliper.  Those spots became my index markers and I then used the drum on the edge sander to grind the barrel until the index marks just disappeared.  I then used a lathe file to smooth the inevitable ripples from the grinder.  The first barrel I did was a bear because, not knowing anything about barrel steels used by various makers, I used a straight Green Mountain barrel.  They are made of *#$% tough steel and it took me at least 2 days to do the job.  The other barrels were made of steel easier to work and each one took me about a day.  I would not hesitate to swamp a pistol barrel today, but I'd have to think long and hard about doing another rifle barrel unless no one makes a profile that I require.   I will have to do this for some 16th and early 17th century guns I plan to build.

dave

[Bob Roller]

Yes, you can do it.....good files are the base, and lots of elbow grease......think in terms of hours of filing, like one hour per flat. It's like anything in this hobby...we start with the raw product, and work until it's done the way we desire.
Good challenge!
But it IS like eating elephant......one bite at a time!

Marc n tomtom

Sounds like good upper body and breathing exercise.Sharp files are a MUST.
I wonder if a big,sharp Vixen file would work to shorten the job. About sixty
years ago I filed a pistol barrel from round to octagon but wouldn't try it now.
I have an octagon 25 caliber barrel that I MILLED from a short section of a
Douglas center fire barrel and then filed it to give a raised rib effect and then
made an English bolster breech.It's dated 1979.This little barrel is made of 4150
I think and was 1.281 diameter to start with.
Like eating an elephant.......more like the cat ate the grindstone,a little at a time.

Bob Roller

[Old Ford2]

I'm sure it is much more practical to purchase a barrel already swamped.
Doing it by hand, file, and paper would definitely take considerable time and effort.
I have tapered a pistol barrel with a milling machine, that was easy enough.
The barrel was 1 1/8" at the breech and tapered to 1" at the muzzle, the over all length was 10".
The end result is a nicely balanced .69 cal. pistol of large caliber.
I look forward to taking my hand at a rifle barrel.
The purpose to do so, is to say that I did, with a machine.
With the setup in mind, I have great respect to those who do it by hand.
Fred

[Pete G.]

I did this for a SMR. It takes a while but perseverance will pay off. You need a good wide file and a good straight edge as a gauge to keep from getting ripples.

You can use a swamped barrel and build a nice rifle, but the modern swamped profile makes it very difficult to keep the proper architecture around the side panels and wrist on this style gun.

[Dr. Tim-Boone]

Pete G. please say some more about why the modern swamped barrel makes it difficult to get the right architecture around the side panels and wrist.... I may be the only one who doesn't understand..... but I need more of an explanation.

[Gaeckle]

Aside from doing this yourself, is there anybody out there that can do this from a known shop? I do have a very inexpensive barrel that I would like to swamp....a 1 1/8 inch 50 caliber that is 36 inches long. I'd like to reduce the leangth and swamp it and make a jaeger out of it. My cost on the barrel is very low and it's a Green Mountain.

[Daryl]

I've never attempted to file out a swamped barrel, but I once filed a round barrel into a 1/2 round, 1/2 tapered octagonal barrel by filing. It was a LOT of work even though I did not file the bottom 3 flats of the octagonal end.

[gunmaker]

I was wondering about hand swamped bbl. myself.  Is it possible to only do the top 5 flats on a rifle  bbl. ?  Will it flex/bend ?  Does seem like a lot a work, grinder or files....Tom

[Acer Saccharum]

Top five flats only:

My opinion: When the barrel heats up from firing, you want to have even wall thickness, or you can have a curving barrel effect. It goes back to normal when it cools off.

If you're re-enacting, who cares. If youre target shooting, you may experience vertical stringing.

[smart dog]

Hi,
Most good target shooters I know believe a straight barrel is the most accurate for the reason described by Tom.  Some also mention "barrel harmonics", although few of my shooting friends can explain what that means.  Anyway, I swamped my first barrel because I bought a straight octagon to save money, and then decided I really wanted a swamped barrel, so I ground it.  Of course I first made sure I had enough barrel wall thickness to keep it safe.  I swamped other barrels since for the simple reason that no one made the right profile.

dave

[P.W.Berkuta]

I did a 7/8"X 36" .40 cal Green Mountain barrel. I used a milling machine to rough out and then files to get the shape I wanted. It was a BIG PITA and not worth the effort. It shoots OK but I'll buy my swamped barrels from now on -- Oh and it took me a little over 4 days to complete .

[D. Taylor Sapergia]

Bob Roller has the right idea about files:  the Vixen file has very course aggressive curved teeth that go from side to side of the file.  Each tooth acts like a plane, and literally chews away the steel.  Use the Vixen on an angle to the barrel and use the whole length of the file on each stoke - cuts like a milling machine, and leaves a pile of curled cuttings on the bench.

[Pete G.]

Pete G. please say some more about why the modern swamped barrel makes it difficult to get the right architecture around the side panels and wrist.... I may be the only one who doesn't understand..... but I need more of an explanation.

The modern profile swamped barrel is usually thicker at the breech and the more pronounced swamp produces more of an angle. This ends up kicking the tail of the lock out from the centerline, which is fine for earlier styled Pennsylvania rifles, particularly if you are attempting to get the wrist wider than tall, but the later styled Southern rifles tend to be more slender through this area, usually noticeably thinner than high. Granted, the swamped barrel will produce a better balanced rifle, but most of the old southern style rifles I have handled tend to feel a little nose heavy because of an almost straight barrel and a very slender butt stock.

[JTR]

I agree with the other guys that doing it yourself is a major PITA, and hardy cost effective, unless your time is worthless, sort of like mine! I've done several by hand with a vixen file, and the last one with a big hand grinder guided along the edge of a template. After the majority was ground away, out came the files, and muscle.

Gunmaker mentioned just doing the top five flats. I have a nice old swamped barrel, signed J Dickert, with only the top five flats swamped. The bottom three flats are straight as an arrow with the typical stone grinding marks still on them. Needless to say, I have no idea how well it shot, but Dickerts were noted for their accuracy.

John

 

[Jim Kibler]

I've done a number with a mill.  It takes a couple of days to do a good job, but you can create whatever profile you want and not have to wait on barrel makers.

Jim

[okawbow]

My latest build, a Tennessee, with a 3/4" barrel, has a slightly swamped,(1/16") that I filed in 1 afternoon. It's just enough so I can see and feel the difference, and well worth the time. I've read that many southern rifles had just about that amount of swamp. The muzzle is the same dia. As the breech.

[shortbarrel]

I have filed many barrels that I have made, tapered , swamped and straight. If you don't have the time and patience, buy a barrel.

[Mark Elliott]

It has long been my thought that a swamp in the barrel was not a necessarily design as much as it was a consequence of the method of making the barrel; first in forging out the skelp; then forging the flats onto the welded tube; and then filing the flats after the barrel had been reamed and rifled.   You are probably going to end up with a little swamp in the thickness of the skelp, and the thickness of the welded tube, no matter how hard you try to make it even from one end to the other.   The same with filing the flats, assuming that you start filing from the ends and work toward the middle. You would do this both because of the limitation of your reach and wanting the wall thickness to be even at the ends of the barrel, particularly the muzzle.   Consequently,  I don't think any more filing was done than necessary to end up with an even wall thickness at the muzzle and smooth, even, flats elsewhere.   

It seems to me that barrels became straight(er) or straight tapered when they were machine ground and not hand filed.  At least that is my take on the matter.   Any correction from one more informed is always welcomed. 

[Jerry V Lape]

Here is how I would do it.  I would sell it in the items for sale forum and use the money to buy one from one of the custom makers to whatever profile suited me.  It is great to be able to say I made this gun but filing a profile is not making a barrel.  Besides, you had better be prepared to achieve the profile accurately with respect to the bore so you have safe thickness all around and that is going to take special measuring system before I would be comfortable with shooting it.  Might ask another question before beginning - will filing this barrel to a swamped possibly release stresses and change the run out of the bore? 

[Karl Kunkel]

If you didn't swamp the barrel equally across each flat, couldn't you induce or release stresses in the barrel steel that could result in a curve or bow to the bore?

Disclaimer: I only know enough to be dangerous, but I did stay at a Holiday Inn. Straighten me out if I'm wrong.