Long or short barrel

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unnervingfalcon

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It seems to me with all the reading that I have been doing about precision rifles. That a short barrel would be more accurate because there should be less M.O.A.. The rate of travel at the end of a long barrel would be more than with a short, if everything were equal. Is this correct??
 
In spite of everything you read, every barrel has its time, or more commonly known as a node. Deflection, stiffness, and other factors, I can't comment on, as I don't really know, but having said that, I don't really buy into it. I am not sure as to what you are calling MOA.
There are a few ways to decide on a barrel length, and first should be purpose. If its a hunting rilfe, cut the barrel to the length that balances the rifle.
On a target type rilfe, where weight and balance doesn't matter as much, a longer barrel may want to be more desirable, again depending on use.

Any barrel, in terms of length, can be made to shoot accurately.

R.
 
long or short it wont make a different once you find the node.. dont find the node, dont shoot to the tru potential of the rifle, simple as that..

a load could technically be accurate in both or inaccurate in both, there really isnt a rhyme or reason to it

longer barrels tend to produce a small amount more velocity then the exact same load in a short barrel, but in real world its negligable
 
Rman said:
In spite of everything you read, every barrel has its time, or more commonly known as a node. Deflection, stiffness, and other factors, I can't comment on, as I don't really know, but having said that, I don't really buy into it. I am not sure as to what you are calling MOA.
There are a few ways to decide on a barrel length, and first should be purpose. If its a hunting rilfe, cut the barrel to the length that balances the rifle.
On a target type rilfe, where weight and balance doesn't matter as much, a longer barrel may want to be more desirable, again depending on use.

Any barrel, in terms of length, can be made to shoot accurately.

R.
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Talking about target shooting.

From what I read the Minute of Angle. Or the vibration of the barrel determines how the tip of the barrel moves when the bullet exits it. The less the vibration, the better the accuracy.

Or if the fps is faster for the bullet. The M.O.A. has less time to react. This is why .223 wssm is considered more accurate than .223 win.
 
Or if the fps is faster for the bullet. The M.O.A. has less time to react. This is why .223 wssm is considered more accurate than .223 win.
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So using that theory the 223wssm should be considered more accurate than the 22ppc. I am not aware of that being a common belief among target shooters.You might want to rethink that theory.
 
stubblejumper said:
So using that theory the 223wssm should be considered more accurate than the 22ppc. I am not aware of that being a common belief among target shooters.You might want to rethink that theory.
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I'm new at this and was just trying to figure out some things.

This post is about the barrel length and how and vibration of the barrel changes the angle of the exit of the bullet. It just seems to me that a faster bullet means less of a angle change at the tip of the barrel because the bullet is leaving the gun faster.
 
unnervingfalcon said:
Talking about target shooting.

From what I read the Minute of Angle. Or the vibration of the barrel determines how the tip of the barrel moves when the bullet exits it. The less the vibration, the better the accuracy.

Or if the fps is faster for the bullet. The M.O.A. has less time to react. This is why .223 wssm is considered more accurate than .223 win.
Click to expand...

From Wiki, so it may or may not be correct, but it looks about right: "Minute of angle (MOA) is the measurement (in fractions of degrees) of a ballistic round's deviation from its initial heading due to gravity and/or the effect of air resistance on velocity. Informally known as a "Bullet's Trajectory" or "the rainbow effect". Long range weapons must account for this effect because a fired round falls at a quadratic rate. "

This is considered to be exterior ballistics.
What you are addressing is interior ballistics.

So, I am not sure what that would have to do with barrel harmonics. One of the best explainations on barrel harmonics, was also the most simple. Picture an old school radio tower with guy wires on it. Stand at the bottom of one of those wires, and shake it, once. A pulse will go up the wire, hit the end, and come back down. The longer the wire, the longer the time for the pulse to return, the shorter, the faster.
This is the same in a gun barrel. The trick is to determine the optimum time for the barrel, when the pulse is flat, as the bullet exits the barrel. This depends on the length. The diameter of the barrel has little to no effect on this measurement.
The most common way to determine this is a ladder test, where a bunch of different loads are made up, shot, and either measured over a chronograph, or in absence of a chrony, group size measured. The former being more accurate.
I run a proven calculation that gives me a barrel time in miliseconds. This time is then compared to load data in Quickload, and a velocity is determined. I then make loads up in order to find this velocity. The chronograph then determines velocity and dispersion. When the dispersion is at its smallest, say a spread of 15 to 25fps, or prefferably less, then the node is found. This is the same as the ladder test, except that less rounds are loaded in order to find the node.
As I said, every barrel, regardless of length, has it's time, or node. Length, in a rifle application, should not be a determining factor in accuracy.

R.
 
Rman said:
From Wiki, so it may or may not be correct, but it looks about right: "Minute of angle (MOA) is the measurement (in fractions of degrees) of a ballistic round's deviation from its initial heading due to gravity and/or the effect of air resistance on velocity. Informally known as a "Bullet's Trajectory" or "the rainbow effect". Long range weapons must account for this effect because a fired round falls at a quadratic rate. "

This is considered to be exterior ballistics.
What you are addressing is interior ballistics.

So, I am not sure what that would have to do with barrel harmonics. One of the best explainations on barrel harmonics, was also the most simple. Picture an old school radio tower with guy wires on it. Stand at the bottom of one of those wires, and shake it, once. A pulse will go up the wire, hit the end, and come back down. The longer the wire, the longer the time for the pulse to return, the shorter, the faster.
This is the same in a gun barrel. The trick is to determine the optimum time for the barrel, when the pulse is flat, as the bullet exits the barrel. This depends on the length. The diameter of the barrel has little to no effect on this measurement.
The most common way to determine this is a ladder test, where a bunch of different loads are made up, shot, and either measured over a chronograph, or in absence of a chrony, group size measured. The former being more accurate.
I run a proven calculation that gives me a barrel time in miliseconds. This time is then compared to load data in Quickload, and a velocity is determined. I then make loads up in order to find this velocity. The chronograph then determines velocity and dispersion. When the dispersion is at its smallest, say a spread of 15 to 25fps, or prefferably less, then the node is found.
As I said, every barrel, regardless of length, has it's time, or node. Length should not be a determining factor in accuracy.

R.
Click to expand...

Thanks.... that answers my question
 
This post is about the barrel length and how and vibration of the barrel changes the angle of the exit of the bullet. It just seems to me that a faster bullet means less of a angle change at the tip of the barrel because the bullet is leaving the gun faster.
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You are making assumptions that aren't true. How consistently the bullet leaves the barrel effects accuracy, not how quickly the bullet leaves the barrel. The bullet can't leave the barrel fast enough to avoid harmonics.
 
I run a proven calculation that gives me a barrel time in miliseconds. This time is then compared to load data in Quickload, and a velocity is determined. I then make loads up in order to find this velocity. The chronograph then determines velocity and dispersion. When the dispersion is at its smallest, say a spread of 15 to 25fps, or prefferably less, then the node is found. This is the same as the ladder test, except that less rounds are loaded in order to find the node.
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And most of the time that works, but I have also found loads, that although they don't have the smallest velocity spread, they shoot smaller groups in my gun out to 400 or 500 yards. Unfortunately, reloading is not an exact science.
 
Math would tell us that the lower the velocity spread, the greater accuracy. This would prove out even more over longer distances. It's not me saying this, but its the law! Of gravity and physics. I may suggest you are seeing chrongraph error or something else to that effect?
But yes, you are correct in that reloading is not an exact science, but it can be tighter then most experience. It is difficult to manage all of the variables.

R.
 
The variables are too numerous to consider to get it exactly right. As long as the barrel is consistent from shot to shot the poi will vary very little. Fwiw a slower bullet can actually spend less time in a barrel than a faster bullet.
 
Math would tell us that the lower the velocity spread, the greater accuracy.
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Unfortunately,sometimes our guns don't listen.:D

If that really worked 100% of the time, we would always be able to find the most accurate loads without ever firing a bullet at a target.However, I haven't found that to be the case.

I may suggest you are seeing chrongraph error or something else to that effect?
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That isn't the case. As much as I would like to be able to explain it I can't.
 
It isn't the barrels job to be consistant, rather, it is what you feed it. The barrel is one of the few constants a relaoder has to work with. The problem is, depending on cartridge choice, it may not stay that way for long.
How can a bullet with less velocity, spend less time in a barrel than a bullet with more velocity?
If it's twist rate, then it isn't the same barrel, and I don't understand the point as it pertains to the conversation?

R.
 
stubblejumper said:
Unfortunately,sometimes our guns don't listen.:D

If that really worked 100% of the time, we would always be able to find the most accurate loads without ever firing a bullet at a target.However, I haven't found that to be the case.



That isn't the case. As much as I would like to be able to explain it I can't.
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I couldn't agree more on your first statement, and I don't totally disagree with you on the second, even though it is mathematically impossible.
How's that? :D

R.
 
If you're just getting into long range shooting I wouldn't be overly worried about barrel harmonics, average muzzle velocity, or other facets of interior ballistics. Focus on understanding the fundamentals of marksmanship, and learning about exterior ballistics (windage, bullet drop, ballistic coefficient, spin drift, etc.) These will be far greater factors in determining the MOA of you and the rifle (I say this because if you have a 2 MOA shooter firing a 0.5MOA rifle you will only produce 2 MOA). But most importantly, have fun!w:h:
 
There are other factors that are *much* more important than the length of the barrel.

To a first approximation, the length of the barrel does not matter. Keep in mind that better than half-MOA results can be gotten from a 30" barrel.

Once a whole lot of the big things are taken care of and you are looking for the very last little bit of accuracy (say, you have a rifle that shoots .4 MOA and you'd like to try to get it to shoot 0.35 MOA), it is worth looking at the small things. Barrel length is one of these small things (unless it is an extra-small thing). At this level, a shorter barrel will have a bit of an advantage because it is stiffer and it flexes less.
 
In terms of stiffness and less "whip", a short thick barrel has the advantage. This is why you see BR guns with extra heavy, but relatively short barrels. But as others have mentioned, there are other considerations. Primarily I would think of purpose. Is it a strict "Bench Gun" or will it see varminting use? Perhaps it's a walking rifle. Weight is a sure consideration if you plan to carry it. 7 days of toting a 300WM R700 sendero with bi-pod, 4.5-30x scope and cheek rest/buttstock pouch and ammo had me looking at other rifles for walking based hunting.

Next come calibre considerations. Again, these will be affected by purpose. 300M bug holes? Perhaps a 6BR, making elk drop like a sack of onions at 1000 yards? Some form of 338 magnum.

Internal Ballistics are a special brand of Shooter Voodoo that really only need to be considered by guys going for the last .1 MOA (minute of angle/arc) in top end competitions.

With proper load development, many factors can be eliminated.

Long barrels allow you to squeeze out the last bit of velocity potential. At the expense of more chance of barrel whip, but again, you will be tailoring loads to the gun to "tune in" to the gun's frequency. Changing anything on the gun can effect it's frequency, I once had to re-tweak a load when I changed my scope base out. It's all part of the art.
Most shooters will tell you their best accuracy occurs around 10% lower than max velocity. Fast bullets that don't group well don't do you any good.

Short barrels have shown their worth, so have long. It comes down to personal choice based on purpose, cartridge and goals.
 
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