Bending Barrels

[Pete G.]

Rifle builders (barrel makers actually) go to great pains to straighten any kinks and bumps out of barrel to make them shoot straight. Smoothbore guys routinely bend their barrels to make them shoot straight. Results seem to indicate that both are correct.

What am I missing here ?

[Dr. Tim-Boone]

English???    Well... in both cases they are trying to align the bore....that is straighten it......by bending the barrels..    

[T*O*F]

What is always missing from this discussion is common sense.  Never argue with an ignorant man.  He will drag you down to his level and beat you with experience.

Both straight and bent barrels will shoot "straight."  One will shoot to only "one" point of aim.  Think on it!!

[greybeard]

If a barrel is a bit snakey inside and the last 6 inches is dead straight it should still shoot straight. No???

[whitebear]

Greybeard, it will shoot streight just depends on where the last 6 inches is pointing when the ball comes out, but it will shoot streight to that point.

[gregg]

Rifle builders (barrel makers actually) go to great pains to straighten any kinks and bumps out of barrel to make them shoot straight. Smoothbore guys routinely bend their barrels to make them shoot straight. Results seem to indicate that both are correct.

What am I missing here ?

I think what Pete having a hard time rapping his head around bending a smooth bore to shoot where you want it to? Rifle barrels thru time have had great pains used to keep them straight. I think that where Pete coming from?

[greybeard]

I was assuming the last 6 inches were straight,. but we should never assume anything I would guess.

[David Rase]

Most of the time you can adjust the point of impact on a rifled barrel by adjustment of the sights.  On a smoothbore you sight down the top of the barrel since they normally only have a front sight which is soldered on and is non adjustable.  With non adjustable sights you then either have to remove and resolder the sight to its new position or regulate the barrel.  I have had a couple of rifle barels that needed to be "bent" to bring the sights back to a more centered position on the barrel so "bending" a barrel is not just for smoothbores.
DMR

[Dave Dolliver]

I have been called upon to "fix" a couple of rifle barrels that wouldn't hit the aim point unless the sights were way off center.  Held a straight edge up agaist the outside of the barrel (they were both straight not swamped) and they were obviously bent bysome damaging incident.  It happens.

Usually I am asked to adjust poiny of impact for a fowler or trade gun.  It's probably because the stock does not fit the individual shooter properly.  By bending one can adjust the impact point at a particular distance, but it might well be off a bit when it's shot at a different range.

Dave Dolliver

[Longknife]

BENDING? That's for amatures, I "REGULATE" barrels to shoot to point of aim!!! ...Ed

[Mike Brooks]

I have a old french trade gun barrel ca 1740 - 50 that is as crooked as a snake. Although I'd never shoot it, I suspect it would shoot where you point it.

[Pete G.]

So I take it that the consensus is that a rifle barrel really doesn't have to be straight(within reason of course)? Makes me wonder why there was so much emphasis on straightening barrels.

[T*O*F]

So I take it that the consensus is that a rifle barrel really doesn't have to be straight

Pete,
Remember I 1st said that common sense is missing from the equation.  You can't just assume things from a variety of opinions.  You really have to THINK about it.

A body in motion will continue in motion unless acted upon by an outside force.  When a projectile leaves the end of the barrel, it will travel straight, but is acted upon by gravity, so all projectiles will drop.  Thus, bent or straight barrels will shoot straight.  If there is wind, it will be blown off its trajectory.

With a straight barrel, the bore and the sights are on the same plane, so they shoot where aimed.
With a bent barrel, the bore and sights are on different planes, therefore it will only shoot to ONE point of aim at a specific distance if the bend is right or left.  Bending a barrel up or down has the same effect as raising or lowering the sights, but it will always shoot higher or lower than a straight barrel with properly zeroed sights.  Draw it out and you will understand.

[keweenaw]

If we suppose that a bore has a smooth curve to it, one would never notice if the curve was in the vertical plane.  Sights would be centered on the barrel.  It might shoot a bit higher or lower than another barrel at a distance other than what the sights are adjusted for but we don't get much concerned about that.  If the curve is in the horizontal plane then the sights can't be centered on the barrel and as TOF suggests, it will shoot off in windage at any distance other than that for which the sights are set.   I read an interesting article just yesterday about why we get curved bores.  It has little to do with the deep hole drill bit, if that's set up correctly it will drill a straight hole.  However if the blank being drilled isn't perfectly straight, when it's spun in the lathe/drill machine, it will develop a more pronounced curve due to the centrifugal forces.  The hole goes through straight but when the barrel is not longer being spun it will go back to it's original position and the hole that was drilled through it will be curved.

Tom

[Don Getz]

Tom......good explanation.   When the barrel blank is drilled, if the hole does not come out on dead center, which it rarely
does, it is not a major problem.    The next step in making the barrel to put that drilled blank into a lathe, on centers, and
turn the blank down around the bore, or to make it concentric with the bore.   Now, to complicate that task, if the hole is
quite a bit off center, it willl heat the "fat" side of the barrel more than the thin side, causing it to warp.  It then must be
straightened again before the next step is done in making the barrel.    Turning the blank is one of the most important
steps in  making a good barrel.  ...Don

[Bryce]

Someone correct me if i am wrong, but couldnt bending a barrel lead to reduced accuracy during extended shoots? bending would initially correct the alignment. It would also leave residual stresses within the metal which would naturally try to force the barrel back towards (but not completely to) its original position before bending. Under resting conditions these stresses would not cause a change in the shape or point of aim but as the barrel heats and expands they would likely shift the barrel in a way not typical to the normal working of the barrel.