is there any way to lower the resonance frequency of a long barrel? ive got a 30" stainless barrel that im looking to improve on. the only thing ive seen is a rubber slip on thing that doesnt look like it actually does anything.
Gunsmithing barrel resonance
- Thread starter rockybrashear
- Start date
Re: barrel resonance
This is from Varmint Al's website:
http://www.varmintal.com/atune.htm
"ADDING A TUNER.... Adding a tuner to the muzzle of a rifle barrel does the following:
1. The additional mass reduces the amplitude of the vibrations.
2. Decreases the natural frequencies by decreasing the lower Mode's frequencies more than the higher Modes.
3. Increases the barrel's vertical end sag due to the extra weight. This would tend to make the vertical plane the preferred plane of vibration.
4. Moves the Mode 2 node closer to the muzzle."
Give the Limbsaver Barrel De-Resonator a try, it's not like you would be out a ton of money and it isn't a permanent modification to your rifle.
http://www.midwayusa.com/viewproduct/?productnumber=113779
This is from Varmint Al's website:
http://www.varmintal.com/atune.htm
"ADDING A TUNER.... Adding a tuner to the muzzle of a rifle barrel does the following:
1. The additional mass reduces the amplitude of the vibrations.
2. Decreases the natural frequencies by decreasing the lower Mode's frequencies more than the higher Modes.
3. Increases the barrel's vertical end sag due to the extra weight. This would tend to make the vertical plane the preferred plane of vibration.
4. Moves the Mode 2 node closer to the muzzle."
Give the Limbsaver Barrel De-Resonator a try, it's not like you would be out a ton of money and it isn't a permanent modification to your rifle.
http://www.midwayusa.com/viewproduct/?productnumber=113779
Re: barrel resonance
actually im looking for something thats a little more solid than that. my main concern is that i have a 30" target barrel in 300 win mag and im worried that excessive resonance will be a problem. plus i just borrowed a limbsaver from a friend of mine so im trying it out. but do i have other options?
actually im looking for something thats a little more solid than that. my main concern is that i have a 30" target barrel in 300 win mag and im worried that excessive resonance will be a problem. plus i just borrowed a limbsaver from a friend of mine so im trying it out. but do i have other options?
Re: barrel resonance
Is there actually a problem or are we searching for a solution to a non-issue?
Is there actually a problem or are we searching for a solution to a non-issue?
Re: barrel resonance
Try a 2' piece of 3/4" surgical tubing 80% filled with lead shot and wrapped around the barrel.
But by changing the harmonics you'll change your point of aim.
Try a 2' piece of 3/4" surgical tubing 80% filled with lead shot and wrapped around the barrel.
But by changing the harmonics you'll change your point of aim.
Re: barrel resonance
Many ?'s to be answered as previous posters noted. You basically need to add or subtract mass, damping or stiffness to control the resonant frequencies of a structure/barrel. I could geek out on this guys but I'll spare you. c-;p-8
More info please...
Many ?'s to be answered as previous posters noted. You basically need to add or subtract mass, damping or stiffness to control the resonant frequencies of a structure/barrel. I could geek out on this guys but I'll spare you. c-;p-8
More info please...
Re: barrel resonance
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LoneWolfUSMC</div><div class="ubbcode-body">Is there actually a problem or are we searching for a solution to a non-issue? </div></div>
That was the purpose of my questions above. Very doubtful there's a problem.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LoneWolfUSMC</div><div class="ubbcode-body">Is there actually a problem or are we searching for a solution to a non-issue? </div></div>
That was the purpose of my questions above. Very doubtful there's a problem.
Re: barrel resonance
At benchrest matches I have seen all kinds of things used. Even a 4" thinwall tube and put tension on the barrel.
At benchrest matches I have seen all kinds of things used. Even a 4" thinwall tube and put tension on the barrel.
Re: barrel resonance
im just searching for available options for more accuracy. barrel harmonics are of some concern. its all about tighter groups.
im just searching for available options for more accuracy. barrel harmonics are of some concern. its all about tighter groups.
Re: barrel resonance
What caliber is this?
What caliber is this?
Re: barrel resonance
300 win mag
300 win mag
Re: barrel resonance
There are quite a few "Tuners" showing up at 100,200,300 yd. BR matches. Some are very well designed and some are laughable. Bottom line is they all seem to work the same way. The move the weight forward or backward to "tune" the barrel vibrations to the specific load. I don't use one but have several friends who do or, have tried them. I think at this point the jury is still out, as to whether they are "for real".
There are quite a few "Tuners" showing up at 100,200,300 yd. BR matches. Some are very well designed and some are laughable. Bottom line is they all seem to work the same way. The move the weight forward or backward to "tune" the barrel vibrations to the specific load. I don't use one but have several friends who do or, have tried them. I think at this point the jury is still out, as to whether they are "for real".
Re: barrel resonance
Here is some information that is of some interest from riflebarrels.com...
Rifle Barrels
Not sure on the accuracy or validity of the concepts and data bantied about there but no reason to doubt it either. Generalizations are typically trumped by reality. Physics, if you can measure it and get it modeled right, is undeniable.
Here is some information that is of some interest from riflebarrels.com...
Rifle Barrels
Not sure on the accuracy or validity of the concepts and data bantied about there but no reason to doubt it either. Generalizations are typically trumped by reality. Physics, if you can measure it and get it modeled right, is undeniable.
Re: barrel resonance
Well for a WM you would need at least 20 to 24 ounces of weight to start to be able to control the harmonics of this barrel. But a nice big heavy muzzle break would sure help....
Well for a WM you would need at least 20 to 24 ounces of weight to start to be able to control the harmonics of this barrel. But a nice big heavy muzzle break would sure help....
Re: barrel resonance
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DocEd</div><div class="ubbcode-body">There are quite a few "Tuners" showing up at 100,200,300 yd. BR matches. I think at this point the jury is still out, as to whether they are "for real". </div></div>
Is Tony Boyer using one or has a single BR HOF point been awarded to anyone that is using one?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DocEd</div><div class="ubbcode-body">There are quite a few "Tuners" showing up at 100,200,300 yd. BR matches. I think at this point the jury is still out, as to whether they are "for real". </div></div>
Is Tony Boyer using one or has a single BR HOF point been awarded to anyone that is using one?
Re: barrel resonance
I don't believe that Tony is using one. He is not a fair comparison to use as he is so vastly superior to most other shooters. Hal Drake has been using one on both PPC and 30BR barrels. He has done quite well over the last couple of years. As I said, I don't think that any concrete proof has been established to the value of using a tuner but, that's what the BR game is all about, Experimenting in the quest for extreme rifle accuracy.
I don't believe that Tony is using one. He is not a fair comparison to use as he is so vastly superior to most other shooters. Hal Drake has been using one on both PPC and 30BR barrels. He has done quite well over the last couple of years. As I said, I don't think that any concrete proof has been established to the value of using a tuner but, that's what the BR game is all about, Experimenting in the quest for extreme rifle accuracy.
Re: barrel resonance
Very interesting article at that link.
I think the initial question is valid but premature. We can help questioners with problems, but until we see the evidence and symptoms of the problems, we are limited to dealing with hypotheticals. We tend not to do so well with them.
My experience with tuners has led me to discount their use for practical applications (like hunting, etc.), as opposed to accuracy-only applications (like BR). I find that they can generate amazing accuracy, but that it is not a constant thing. As environmental conditions change, so do the proper tuner adjustments.
If one has the luxury of some sighting/tuning opportunity prior to actually 'going for it', they are very useful. If, however, one is counting on the results of the prior shooting session being valid for a new session, one is often likely to find oneself saying, "what the hell...?" forcefully and repeatedly, unless environmental conditions match between the two sessions.
Such coincidences do not occur with any reliability in my lifetime.
I find that as a practical shooting aid, they are counterproductive. They tend, from a practical viewpoint, to simply result in more rounds being expended overall to achieve the same number of hits.
Greg
Very interesting article at that link.
I think the initial question is valid but premature. We can help questioners with problems, but until we see the evidence and symptoms of the problems, we are limited to dealing with hypotheticals. We tend not to do so well with them.
My experience with tuners has led me to discount their use for practical applications (like hunting, etc.), as opposed to accuracy-only applications (like BR). I find that they can generate amazing accuracy, but that it is not a constant thing. As environmental conditions change, so do the proper tuner adjustments.
If one has the luxury of some sighting/tuning opportunity prior to actually 'going for it', they are very useful. If, however, one is counting on the results of the prior shooting session being valid for a new session, one is often likely to find oneself saying, "what the hell...?" forcefully and repeatedly, unless environmental conditions match between the two sessions.
Such coincidences do not occur with any reliability in my lifetime.
I find that as a practical shooting aid, they are counterproductive. They tend, from a practical viewpoint, to simply result in more rounds being expended overall to achieve the same number of hits.
Greg
Re: barrel resonance
I think you should do a Modal analysis of the barrel by using accel's mounted in various locations of the barrel also dont forget to add some strain gauges to verify high strain areas and compensate for that also. Gain attenuated accels to 5000g's should to the job. Collect the data and then do an FEA to verify the concerned areas. When all the data has been collected you can run a Vibration durability to reproduce resonant frequencies. Once this has been completed you can then make an accurate decision on where to add mass or change materials to compensate for your loss of accuracy if any. Remember when setting up your data aquisition system that you compensate for your signal to noise ratio losses and anti-aliasing. Me personally would collect at 409.6 and 2048 respectivly.
Rich
I think you should do a Modal analysis of the barrel by using accel's mounted in various locations of the barrel also dont forget to add some strain gauges to verify high strain areas and compensate for that also. Gain attenuated accels to 5000g's should to the job. Collect the data and then do an FEA to verify the concerned areas. When all the data has been collected you can run a Vibration durability to reproduce resonant frequencies. Once this has been completed you can then make an accurate decision on where to add mass or change materials to compensate for your loss of accuracy if any. Remember when setting up your data aquisition system that you compensate for your signal to noise ratio losses and anti-aliasing. Me personally would collect at 409.6 and 2048 respectivly.
Rich
Re: barrel resonance
Check out www.powderriverpredators.com and ask them about barrel attitude.
Best of luck,
Macs
Check out www.powderriverpredators.com and ask them about barrel attitude.
Best of luck,
Macs
Re: barrel resonance
If you tell me the material, bore, length, taper, and other dimensions I can give you the first 5 frequencies pretty easily.
Run the FEM analysis, then glue accelerometers on there to verify, not the other way around.
If you tell me the material, bore, length, taper, and other dimensions I can give you the first 5 frequencies pretty easily.
Run the FEM analysis, then glue accelerometers on there to verify, not the other way around.
Re: barrel resonance
OOOoooo fellow engineer/FEA geeks, been playing with this ever since I read an article on barrel length and harmonics. Then the original post followed by late nights playing. GEEKme...
It is a good idea to get a progressive feel/understanding for your specific situation (the physics involved) using FEM/FEA (Simulation). It is pretty simple to use (rocket science under the hood) and guides your steps in the physical world. "What if I do this" hurts the virtual pocketbook less...
Is there such a thing as having too much fun?
OOOoooo fellow engineer/FEA geeks, been playing with this ever since I read an article on barrel length and harmonics. Then the original post followed by late nights playing. GEEKme...
It is a good idea to get a progressive feel/understanding for your specific situation (the physics involved) using FEM/FEA (Simulation). It is pretty simple to use (rocket science under the hood) and guides your steps in the physical world. "What if I do this" hurts the virtual pocketbook less...
Is there such a thing as having too much fun?
Re: barrel resonance
Hell no!
We have been playing with barrel block systems for years now. They work well and have been proven to work with just about anything. It of course it somethings else to mess with and take up more time but when you looking for the perfect group sometimes thats what ya gotta do....
Hell no!
We have been playing with barrel block systems for years now. They work well and have been proven to work with just about anything. It of course it somethings else to mess with and take up more time but when you looking for the perfect group sometimes thats what ya gotta do....
Re: barrel resonance
You have to many varialbles to just run an FEM. Stock, mounting, additional mass, etc... Although it could be done, I feel it is better to actually see what is happening before any changes are made. If you want to do the FEM for accel location that is a good idea and will save a little time.
Rich
You have to many varialbles to just run an FEM. Stock, mounting, additional mass, etc... Although it could be done, I feel it is better to actually see what is happening before any changes are made. If you want to do the FEM for accel location that is a good idea and will save a little time.
Rich
Re: barrel resonance
Too many variables? OH contraire you can get close enough for government work, specifically 40mm cannons. (now i'm gonna have to kill anyone that reads this post, DAMN I HATE THAT WHEN THAT HAPPENS). Free free natural frequencies? floating barrel? Force frequency response? HEHEHE... often times when you break the physics down you find that you can toss out some of the TOO many variables as not contributing significantly to the result. Also remember we are looking for magnitudes of change and not necessarily exact values given a change in the system.
Last week I did a quickie analysis of a mini-14 barrel that paralleled some test data I found. Yep cut 1.5 inches off of the old barrels and the harmonics start to behave ie groups closed up (for a mini-14, ha).
Told ya I bore you to death... C-;
Too many variables? OH contraire you can get close enough for government work, specifically 40mm cannons. (now i'm gonna have to kill anyone that reads this post, DAMN I HATE THAT WHEN THAT HAPPENS). Free free natural frequencies? floating barrel? Force frequency response? HEHEHE... often times when you break the physics down you find that you can toss out some of the TOO many variables as not contributing significantly to the result. Also remember we are looking for magnitudes of change and not necessarily exact values given a change in the system.
Last week I did a quickie analysis of a mini-14 barrel that paralleled some test data I found. Yep cut 1.5 inches off of the old barrels and the harmonics start to behave ie groups closed up (for a mini-14, ha).
Told ya I bore you to death... C-;
Re: barrel resonance
Yeah! Where the dam excitement when you know where its going every time?
Yeah! Where the dam excitement when you know where its going every time?
Re: barrel resonance
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fewenuff</div><div class="ubbcode-body">Too many variables? OH contraire you can get close enough for government work, specifically 40mm cannons. (now i'm gonna have to kill anyone that reads this post, DAMN I HATE THAT WHEN THAT HAPPENS). Free free natural frequencies? floating barrel? Force frequency response? HEHEHE... <span style="font-weight: bold">often times when you break the physics down you find that you can toss out some of the TOO many variables as not contributing significantly to the result.</span> Also remember we are looking for magnitudes of change and not necessarily exact values given a change in the system.
Last week I did a quickie analysis of a mini-14 barrel that paralleled some test data I found. Yep cut 1.5 inches off of the old barrels and the harmonics start to behave ie groups closed up (for a mini-14, ha).
Told ya I bore you to death... C-; </div></div>
I've spent quite a bit of time doing optimization studies and variable reduction studies to figure out exactly what makes the most impact and what are the "asymptotic improvement variables" that we can ignore for the first 97% of the analysis.
You're exactly right IMHO, run the FEM, build some models and let them go on a computer. A frequency analysis, and a forcing function driven analysis like this is very simple and fast to run.
Someone want to get an idea of a barrel analysis, take some measurements for me, I'll make a model and put some results up tomorrow. We can all punch holes in it then. Who's got the actual dimensions of say, a Rem 700 barrel, 30 caliber, heavy varmint contour about 26" long. I'll run that against a straight bull barrel and a little spaghetti barrel for stiffness.
I think that would be a GREAT topic of discussion, let's get the engibeering nerds around here thinking!
My girlfriend doesn't understand my obsession with trickled loads, minute adjustments, punishing myself with recoil for the sake of "shooting groups" or the long hours I've spent sitting in front of my computer at home to
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fewenuff</div><div class="ubbcode-body">Too many variables? OH contraire you can get close enough for government work, specifically 40mm cannons. (now i'm gonna have to kill anyone that reads this post, DAMN I HATE THAT WHEN THAT HAPPENS). Free free natural frequencies? floating barrel? Force frequency response? HEHEHE... <span style="font-weight: bold">often times when you break the physics down you find that you can toss out some of the TOO many variables as not contributing significantly to the result.</span> Also remember we are looking for magnitudes of change and not necessarily exact values given a change in the system.
Last week I did a quickie analysis of a mini-14 barrel that paralleled some test data I found. Yep cut 1.5 inches off of the old barrels and the harmonics start to behave ie groups closed up (for a mini-14, ha).
Told ya I bore you to death... C-; </div></div>
I've spent quite a bit of time doing optimization studies and variable reduction studies to figure out exactly what makes the most impact and what are the "asymptotic improvement variables" that we can ignore for the first 97% of the analysis.
You're exactly right IMHO, run the FEM, build some models and let them go on a computer. A frequency analysis, and a forcing function driven analysis like this is very simple and fast to run.
Someone want to get an idea of a barrel analysis, take some measurements for me, I'll make a model and put some results up tomorrow. We can all punch holes in it then. Who's got the actual dimensions of say, a Rem 700 barrel, 30 caliber, heavy varmint contour about 26" long. I'll run that against a straight bull barrel and a little spaghetti barrel for stiffness.
I think that would be a GREAT topic of discussion, let's get the engibeering nerds around here thinking!
My girlfriend doesn't understand my obsession with trickled loads, minute adjustments, punishing myself with recoil for the sake of "shooting groups" or the long hours I've spent sitting in front of my computer at home to
