Barrel bending

[Robby]

I just finished a .36 cal. flintlock rifle. it is a very slim barrel, 46" long, 13/16" at the breech, 5/8" waists, 3/4" at the muzzle. Yesterday: At 50 yards it is shooting about 7" to the left with a good group, I removed the barrel and made sure there was no interference with the lugs, or binding on the stock. Returned to shooting and moving the sights, both front and rear till i got it on zero, they are so far off the center of the barrel that it is unacceptable to me.
Today: I realigned the sights to the center of the barrel, double-checked for any binging or interference and installed the barrel securing it with the tang screw only. At 50, well actual 46yards it is back where I started, about 7" to the left, good group. I am pretty certain there is nothing in the stock causing the barrel to yaw off the the left, so It must be the barrel itself is bent or not bored in line with itself. I have no practical experience bending a barrel and would appreciate any tips as to how I might do this without ruining the barrel, or if there is something I am missing that I can try before I start the bending, that would also be much appreciated, cuz, I really am intimidated by this whole bending thing.

Robby

[Daryl]

One method is to thump it against a thick parked tree. Another is to bend it until with wedges and clamps until it works.
Another is to prop up each end and stand in the middle. I think that's Mike's method. Taylor has done both, thumping and clamping.
Yet another is using a barrel straightening/bending machine.

[P.Bigham]

Might try removing the breech plug and looking down the bore. You should see concentric rings.  If not it maybe bent.  Numerous ways to straighten it.  Daryls way looks good.

[Daryl]

Taylor's picture & process. Note the upward bend of the bench as well. This did not "bend" the 20 bore barrel, BTW. It needed a bit more.
That's a solid core door for the bench.

[Marcruger]

I know a lot of folks talk about jumping on a barrel or bending on a tree, but the engineer in me likes the C clamps method.  It seems more likely to allow me the "creep up" on the right bend.  I got a bad barrel from a known barrel maker a few years back.  I thought about bending, but instead went with a replacement barrel.  What concerns me with bending a barrel is what stresses are left in the steel once it is bent.  God Bless, and best wishes,   Marc

[Bob Roller]

Years ago at Friendship Bill Large whacked a barrel across a log and cures the problems it had.One picture shows a man and a barrel jack which is used to straighten barrels and tubing.Bill Large had one but rarely used it and it sat for years with little use.Rock Island Arsenal was on a plate bolted to it.

Bob Roller

[Molly]

BOY!  Have we been down that road!  Eventually sent the barrel back to the builder who "stands by his work".  He re-positioned the sight to center and sent it back.  Still shoots about 3 inches to the right with sights centered.  Total disappointment and waste of time and $$ in shipping charges.  In a conversation with a local builder he reasoned that a .015 adjustment to a front sight should result in a correction at 25 yards thus he felt the barrel could be "bent" back to the same degree (.015) and it should shoot straight.  Should not take a lot to make that correction.  I figure if it was shot at 50 yards it would have been off 6 to 7 inches so maybe all you need is a .015 "bend" as well.  Another aspect is at what point along the length do you make the bend?  He reasoned that probably the point to apply pressure and bend it would be about 8 inches back of the muzzle or otherwise at the point where it began to flare out.  I think my husband is up to that but it involves removing the barrel, bending and then set the barrel back in place, going out to test it and then repeat as necessary.  Poo on that.  The gun is to be sold "as is" to a buyer who feel he likes a challenge.  Daryl:  That is some "bend" pictured.  The ball might land behind you!

Good luck!

And for those out there that do not build the lesson here is that no matter how pretty it looks the proof is in the performance.  I'll not mention the builder but I sure won't recommend his work nor buy another from him.  And it is a very good looking rifle.

[Daryl]

Molly - that barrel, once taken off the bench, was not bent. It straightened right out again. It had to be bent further than shown to take a "permanent" bend & make it shoot to the sight(s).
I was with Taylor when he made a Brown Bess barrel shoot straight and to the elevation required. It only took a few whacks on an aspen tree to do it, replacing the barrel, loading and shooting
after each "whack".  Finished in less than an hour.

[AZshot]

I didn't look up the ballistics tables, but to me 7" windage at 50 yds is something you could easily correct with proper sight adjustment.  Make sure the rear notch is centered too, if it was cut off to the side - there're your problem.
If it's hitting left, move the rear sight right, and the front sight left.  It shouldn't take much.  Bending a barrel seems quite extreme.  I'm also not sure that a "non straight" barrel would actually launch a bullet off to the side that much.  The bullet goes in a straight line (plus drop) after leaving the muzzle.  It's not like it flys in a curve if the bore isn't straight.  That's impossible.   I'd check your muzzle for a burr or a problem with the crown.

[Daryl]

The last few inches of the barrel dictate the direction of travel. If they are on an angle to the line of sights, so is the projectile in flight.

[bob in the woods]

I've told this story before, but will repeat it for those who think that barrels remain straight for the life of the gun . Heading off to Rendezvous , my friend was helping load the Jeep.  He put my rifle in , [ soft case] resting hard against a shooting box, and slammed the door.   The match was a write off for me because my shots were hitting the target next to mine at 25 yards !!   Barrel was a .40 A weight . When I got home I was able to "bend it straight " and it was as good as before. It's not as big a deal as many folks think.

[Pukka Bundook]

Indeed Bob,
In my case, I think I have more feel by 'yunking' on the barrel with one end in either a padded vise or in the fork of a tree,
You just spring it steadily until you feel if may have moved a bit.

[WadePatton]

Indeed Bob,
In my case, I think I have more feel by 'yunking' on the barrel with one end in either a padded vise or in the fork of a tree,
You just spring it steadily until you feel if may have moved a bit.

Fork of tree is my choice over whacks.  Bending barrels is as old as gunmaking.

[Herb]

https://americanlongrifles.org/forum/index.php?topic=73012.msg728177#msg728177

[kudu]

I bend barrels quite often I use a system similar to Darrell,but monitor progress with a cheep Dial indicator.

[Daryl]

Kudu - that's Taylor's work. I merely posted the picture.  He has also used an aspen tree's trunk, whacking the barrel against the trunk, the reassembling the gun and shooting it, then repeating as necessary to get it shooting the way he wanted.

[Robby]

My re-re-bent barrel at fifty yards.



I'm pretty happy and relieved. a couple more sessions to assure me that this isn't going to change and I'll tweek the sight's a bit. Thank you all.
Robby

[Daryl]

Nice group. I might have to try that aiming point myself.

[Hungry Horse]

 My experience is primarily with smooth bore shotgun barrels. I went through a stage of building tradeguns out of 30 inch surplus shotgun barrels, and found since they were tapered, they often needed bending. Also because they were new old old old stock that had been shuffled around for a hundred year, some were pre-bent.
 The best tools for bending barrels I could come up with and not spend a couple grand was a cheap bottle jack ( a scissor jack works also), and an EMT bender with the handle removed, and a couple of big old iron “C” clamps, and a string pulled tight to measure spring back.
 There is nothing expensive enough that you can’t modify it to fit your needs, whiteout breaking the bank. I grind the EMT bender to fit my needs, and weld pieces of pipe onto the “C” clamps.
 I’m sure rifle barrels will take a lot more bending to overcome the spring back, and the rigidity of the octagon barrel.

Hungry Horse

[Daryl]

This one, a 20 bore smooth barrel, did not take a bend from this deflection, this time. It sprung back all the way.

[Mule Brain]

I had that issue, tried to bend it and nope. Sent to manufacture and came back worse! Trying again and out of sheer frustration, ended up bending it in the crook of a tree. I shot and bent, shot and bent, then finally got it.