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PPP MMM
Guest
What material would have the best vibration dampening properties to make a stock from, for a long range shooting? The weight is not important. Thanks.
Shoot well
Peter
Shoot well
Peter
A
Alastair
Guest
Having used wood, laminated wood and aluminium. I would suggest wood of some discription. I found that the aluminium stock had a very sharp recoil.
regards
regards
P
PPP MMM
Guest
Gunstocks and gunstock material contribute very little vibration damping if any at all to the total rifle system. Almost all the forcing energy and contributing vibrational activity occurs between the barrel chamber and the barrel muzzle................that is the area where all damping and tuning needs to take place except for offset mass forcing................Don
If you go onto the Varmint Al site you will see just how vibrational characteristics of the stock affect barrel and receiver vibration. There have also been several posts by varmint Al on this forum showing how stocks of different materials affect vibration. Mass,dimensions, and bedding characteristics of the stock also affect vibration. All of V.A.'s analysis deals with the recoil effect on vibration rather than the bullet's effect but it still demonstrates the influence of stock material properties.
Comparison?
Has anyone ever tried a true comparison....you know...someone with lots of time, talent, and money? Taken a true bench quality barreled action (or two, or five
) and fit different stocks, like glass, wood laminate, wood/carbon fiber laminate, aluminum, ect., and did a true accuracy test?
That test would draw a crowd of interested shooters!! It seems that everyone has thier own idea or opinion.
Has anyone ever tried a true comparison....you know...someone with lots of time, talent, and money? Taken a true bench quality barreled action (or two, or five
) and fit different stocks, like glass, wood laminate, wood/carbon fiber laminate, aluminum, ect., and did a true accuracy test?That test would draw a crowd of interested shooters!! It seems that everyone has thier own idea or opinion.
P
PPP MMM
Guest
Tod
I've done limited testing of different stock materials and I wasn't very successful. The main reason behind this was contributed by the fact that I don't load my ammo to the benchrest quality as I don't sort brass, bullet bearing surface, I use powder thrower after the selected charge is weighted, I don't turn necks and I only use Sierra SPBT hunting bullets. So my best loads have considerable variations from shot to shot. My best loads/rifle combinations would shoot around 20-25mm/100metres. (0.8-1"/110yards). My rifles only weigh around 4-5kg. (9-11pounds)
However I've found, that there is a impact point difference between hard/soft rest and where the rest is positioned. The harder the rest is and the closer the rest is towards the action the further the group w'll shift in the opposite direction of the rest and from the point of aim. Resting rifle on its left side agains the tree will shift the group to the right. My .308 w'll shift the group comparativly less than my .375H&H w'll. So my conclusion is that if different rest materials have contributed towards the change of point of impact, there must be some relation regarding the stock materials also. A laminated stock has virtually no sound, a plastic/fibreglass stocks have a distinctive echo sounds and wood stocks sound varies from stock to stock. The main vibrations may be in the steel between the action and the muzzle, but I have a feeling that the stock is involved somewhat as well.
Shoot well
Peter
I've done limited testing of different stock materials and I wasn't very successful. The main reason behind this was contributed by the fact that I don't load my ammo to the benchrest quality as I don't sort brass, bullet bearing surface, I use powder thrower after the selected charge is weighted, I don't turn necks and I only use Sierra SPBT hunting bullets. So my best loads have considerable variations from shot to shot. My best loads/rifle combinations would shoot around 20-25mm/100metres. (0.8-1"/110yards). My rifles only weigh around 4-5kg. (9-11pounds)
However I've found, that there is a impact point difference between hard/soft rest and where the rest is positioned. The harder the rest is and the closer the rest is towards the action the further the group w'll shift in the opposite direction of the rest and from the point of aim. Resting rifle on its left side agains the tree will shift the group to the right. My .308 w'll shift the group comparativly less than my .375H&H w'll. So my conclusion is that if different rest materials have contributed towards the change of point of impact, there must be some relation regarding the stock materials also. A laminated stock has virtually no sound, a plastic/fibreglass stocks have a distinctive echo sounds and wood stocks sound varies from stock to stock. The main vibrations may be in the steel between the action and the muzzle, but I have a feeling that the stock is involved somewhat as well.
Shoot well
Peter
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If you will notice in all of Al's modeling, nowhere does he give a contributing percentage estimation of the gunstocks effect on the entire rifle system during the firing event, probably very hard to determine with all the other components involved................Don
Stocks contribution to vibration...
If you will notice in all of Al's modeling, nowhere does he give a contributing percentage estimation of the gunstocks effect on the entire rifle system during the firing event, probably very hard to determine with all the other components involved................Don
Okay Don, I might as well start another big ho ha!
In a vibration analysis as Varmint Al has done I think you will find basically the stock is responsible for 100% of the vibration effect. That is, if you mount a barreled receiver in a perfectly rigid stock, where the receiver would in effect be cantilevered from the stock then in theory you would get ZERO RECOIL vibration pattern of the type that V.A.'s FEA produces.
You have to remember V.A. analysis does not show the vibration that results from a bullet's inertia effect in a curved barrel. This means if you rigidly support the receiver there will be essentially no vibration transmitted from the bolt to the receiver to barrel. There may be some sound or compression high frequency motion transmitted out to the barrel but that isn't the vibration mode that everybody is trying to affect with tuners.
If you will notice in all of Al's modeling, nowhere does he give a contributing percentage estimation of the gunstocks effect on the entire rifle system during the firing event, probably very hard to determine with all the other components involved................Don
Okay Don, I might as well start another big ho ha!
In a vibration analysis as Varmint Al has done I think you will find basically the stock is responsible for 100% of the vibration effect. That is, if you mount a barreled receiver in a perfectly rigid stock, where the receiver would in effect be cantilevered from the stock then in theory you would get ZERO RECOIL vibration pattern of the type that V.A.'s FEA produces.
You have to remember V.A. analysis does not show the vibration that results from a bullet's inertia effect in a curved barrel. This means if you rigidly support the receiver there will be essentially no vibration transmitted from the bolt to the receiver to barrel. There may be some sound or compression high frequency motion transmitted out to the barrel but that isn't the vibration mode that everybody is trying to affect with tuners.
W
WINMOD70
Guest
How are you holding the rifle, recoil control needs to be considered.
T
tim in tx
Guest
i will add one more
torque needs to be considered as well for poi change . tim in tx
torque needs to be considered as well for poi change . tim in tx
Where does Varmint Al say this?
Ive seen Al's modeling effects of bullet torque, barrel droop, scope/mount offset, and barrel pressurization.........I am pretty sure these effects eat into that 100 % gunstock contribution to the vibration effect.
Nowhere, do I remember Varmint Al modeling the material and structural differences between wood, fiberglass, carbon fiber, lamenant hybreds or other materials as they relate to rifle systems, in fact, I think he has stated several times that his gunstock modeling of materials and structures has been of a generic nature only accounting for general outer shape and weight, due to the complexities involved in the entire modeling process.............Don
P
Pokerplayer
Guest
The material that would have the best resonance value would be lead.
T
tim in tx
Guest
pacil
i think you have it backwards,als test was freehanging not resting on its forearm.the stocks had nothing to do with it. i have tested these theories and i can tell you with out a doubt that a stock if bedded identicaly to an action does not effect the tune when switching out the barreled action to 3 kinds of stocks, but will effect tracking certainly,the vibration dampining i am worried about is between shots,i dont like the idea of shooting with a remaining resonence from the last shot ,that is the only way a stock material can effect the vibration of the barreled action is in duration not intensity .i generally can feel the shock of the internal explosion with laminated wood or solid wood the least.the resonence with wood w/epoxie bed will last about 2-4 seconds after firing,carbon fiber goes a bit longer,fiberglass falls in between.honeycomb cutting in the fore arm does help to shorten the resonence in the non metal stocks.speedy told me of this and it worked wonderfully upon testing.hope this helps sir. tim in tx
i think you have it backwards,als test was freehanging not resting on its forearm.the stocks had nothing to do with it. i have tested these theories and i can tell you with out a doubt that a stock if bedded identicaly to an action does not effect the tune when switching out the barreled action to 3 kinds of stocks, but will effect tracking certainly,the vibration dampining i am worried about is between shots,i dont like the idea of shooting with a remaining resonence from the last shot ,that is the only way a stock material can effect the vibration of the barreled action is in duration not intensity .i generally can feel the shock of the internal explosion with laminated wood or solid wood the least.the resonence with wood w/epoxie bed will last about 2-4 seconds after firing,carbon fiber goes a bit longer,fiberglass falls in between.honeycomb cutting in the fore arm does help to shorten the resonence in the non metal stocks.speedy told me of this and it worked wonderfully upon testing.hope this helps sir. tim in tx
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Good point Tim.............not only the forearm but also the rear heel. This is something that has always bothered me about Al's modeling, as it pertains to true benchrest rifle shooting as discussed on this forum, where the gun is shot off front and rear rests. None of Al's modeling seems to have taken into account that the gunstocks are almost always used in a 2 support point system, front and rear rests, that I can remember.................Don
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Alastair
Guest
I remember reading in PS a few years a go a big name (can't remember who) 1000yrd BR shooter was moving away from Alloy stocks and going to laminated wood due to the difference in recoil.
I found with my alloy stock it rang like an aluminium baseball bat when fired and I had trouble getting it to shoot consistently.
I found with my alloy stock it rang like an aluminium baseball bat when fired and I had trouble getting it to shoot consistently.
To Don and Tim in Tx......
It's a shame all of you don't really LOOK at the work Varmint Al is doing. You can't go off "half cocked" and simply comment on it with out really taking the time to study and understand it.
The rifle he modeled was NOT "free Hanging" it was supported at forearm and heel exactly like a bench rest gun. He even told you, if you take time to read, the size of the support. He also showed what effect supporting it at different points on the forearm would have.
He DID demonstrate the effect of different stock materials by putting in different properties for the stock material. He showed what effect this had on barrel vibration. It's all right there if you will just take time to read it!
As to the per cent of the stock's effect on vibration, if you will take the time to study and think about what V.A. is trying to show you, you will see that the vibration is a result of the moment about the center of gravity of the stock. If you reduce this moment to zero, you have no vibration. The effect of the stock dimensions and stiffness has almost 100% influence on vibration.
I'm not trying to say his model replicates a real life rifle. I doubt anyone could ever do that. You have to learn what you can from what he has done and decide where it might differ from the real thing. Before you do that, however, you have to take the time to find out what is in V. A.'s model.
It's a shame all of you don't really LOOK at the work Varmint Al is doing. You can't go off "half cocked" and simply comment on it with out really taking the time to study and understand it.
The rifle he modeled was NOT "free Hanging" it was supported at forearm and heel exactly like a bench rest gun. He even told you, if you take time to read, the size of the support. He also showed what effect supporting it at different points on the forearm would have.
He DID demonstrate the effect of different stock materials by putting in different properties for the stock material. He showed what effect this had on barrel vibration. It's all right there if you will just take time to read it!
As to the per cent of the stock's effect on vibration, if you will take the time to study and think about what V.A. is trying to show you, you will see that the vibration is a result of the moment about the center of gravity of the stock. If you reduce this moment to zero, you have no vibration. The effect of the stock dimensions and stiffness has almost 100% influence on vibration.
I'm not trying to say his model replicates a real life rifle. I doubt anyone could ever do that. You have to learn what you can from what he has done and decide where it might differ from the real thing. Before you do that, however, you have to take the time to find out what is in V. A.'s model.
T
tim in tx
Guest
pacel sir
well i owe you an aplogy, i went to als website and on his latest full rifle test he does show a wood stock to be supported at this time. i had talked to him on this subject a few years back at that ime he said all models were free hanging like and he said it was just too hard to model the effects of the stock in poi along with other varibles like bags,friction, rest and table. too many varibles,eveidently he has found some modeling perimeters for the stock to be used in the calculations. tim in tx
well i owe you an aplogy, i went to als website and on his latest full rifle test he does show a wood stock to be supported at this time. i had talked to him on this subject a few years back at that ime he said all models were free hanging like and he said it was just too hard to model the effects of the stock in poi along with other varibles like bags,friction, rest and table. too many varibles,eveidently he has found some modeling perimeters for the stock to be used in the calculations. tim in tx
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tim in tx
Guest
pacil,here is the post i refer to in 07
Quote:
Originally Posted by tim in tx
if a barrel were suported 13 inches out from the action face by way of magnetic force would ,how would it affect the muzzle deflection? tim in tx
There is no front or rear rest. The rifle is hanging from springs. It is a Free-Free condition with no contact to ground. Remember that the deflections are multiplied by 1000X so one can easily see the motion.
Even with the rifle suspended in air, the muzzle points to about the same location when the bullet exits the barrel. I don't know how to use magnetic suspension in the FEA LS-DYNA code. I think it would behave about the same as the Free-Free condition.
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Good Hunting... from Varmint Al
Quote:
Originally Posted by tim in tx
if a barrel were suported 13 inches out from the action face by way of magnetic force would ,how would it affect the muzzle deflection? tim in tx
There is no front or rear rest. The rifle is hanging from springs. It is a Free-Free condition with no contact to ground. Remember that the deflections are multiplied by 1000X so one can easily see the motion.
Even with the rifle suspended in air, the muzzle points to about the same location when the bullet exits the barrel. I don't know how to use magnetic suspension in the FEA LS-DYNA code. I think it would behave about the same as the Free-Free condition.
__________________
Good Hunting... from Varmint Al