A curly one that may be hard to prove beyond doubt but there has been a lot of talk regarding tuners or barrel weights recently.
I've used HV and 32" 1.25" parallel barrels with good success but I feel that the 2 parallels had an edge overall and tuned well.
Assuming the rifle will make weight with either option has anyone found evidence that a tapered barrel with a weight will regularly shoot better than a 1.25"?
Is the muzzle weight an overthrow of running a tapered barrel and trying something for extra dampening / overall gun weight and it worked or are some using it as a preferred option over a parallel with the same effective weight?
parallel barrel vs taper with a tuner
Moderator: Mod
-
Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
- Been thanked: 1 time
Adam, wow so many variables to consider in this question! Its really a question of design as to what would work best with what.
What mode and frequency you want to tune for depends on what barrel taper, material, calibre, (hole size) and load you want to use. It requires a pretty comprehensive knowledge of mechanical engineering just to know what question to ask before an answer could be considered.
I'm sure you have seen this already http://www.varmintal.com/atune.htm
I have both tapered and parallel barrels with tuners attached and all I can tell you is that both work well. You can open up and close groups at will by adjusting the tuners on these barrels. I cant see any advantage in accuracy in using one barrel over another. All I know is that in F-Open the parallel barrels offer a larger heatsink for dissipating heat and the increased weight means its an easier task in reaching 10kg to minimise recoil.
Load tuning achieves the same thing and is a necessary first step even with a barrel tuner attached. I really think the only advantage of using a barrel tuner is for when you travel with pre-loaded ammo that is found to be slightly out of tune, (groups have opened up). Then you can quickly close the group back down again without reloading your ammo.
Ian
What mode and frequency you want to tune for depends on what barrel taper, material, calibre, (hole size) and load you want to use. It requires a pretty comprehensive knowledge of mechanical engineering just to know what question to ask before an answer could be considered.
I'm sure you have seen this already http://www.varmintal.com/atune.htm
I have both tapered and parallel barrels with tuners attached and all I can tell you is that both work well. You can open up and close groups at will by adjusting the tuners on these barrels. I cant see any advantage in accuracy in using one barrel over another. All I know is that in F-Open the parallel barrels offer a larger heatsink for dissipating heat and the increased weight means its an easier task in reaching 10kg to minimise recoil.
Load tuning achieves the same thing and is a necessary first step even with a barrel tuner attached. I really think the only advantage of using a barrel tuner is for when you travel with pre-loaded ammo that is found to be slightly out of tune, (groups have opened up). Then you can quickly close the group back down again without reloading your ammo.
Ian
__________________________________________
A small ES is good. A small SD is better. A small group is best!
A small ES is good. A small SD is better. A small group is best!
-
Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
- Been thanked: 1 time
Adam
I sure you are aware my "tuners" are more to add mass which in turn widens the accuracy node by means of acting as a dampener.
Myself and others here in OZ have proved this beyond doubt.
Marty has his fixed as non adjustable and that's what I will be doing this time.
I believe fine tuning a barrel at 1000yds is virtually impossible with a barrel tuner. Remember, it is what happens at the target that counts.
Cam
I sure you are aware my "tuners" are more to add mass which in turn widens the accuracy node by means of acting as a dampener.
Myself and others here in OZ have proved this beyond doubt.
Marty has his fixed as non adjustable and that's what I will be doing this time.
I believe fine tuning a barrel at 1000yds is virtually impossible with a barrel tuner. Remember, it is what happens at the target that counts.
Cam
Last edited by Cameron Mc on Mon May 26, 2014 9:35 pm, edited 1 time in total.
-
BATattack
- Posts: 1345
- Joined: Mon Dec 29, 2008 10:29 pm
- Has thanked: 92 times
- Been thanked: 280 times
Cameron Mc wrote:I will have feedback once I fit my 1.25" bartlein and weight attached.
I am keen to know as well as my other barrels are HV profile. I will try first without weight then with. I have no doubt it will widen the accuracy window as with the other 7 x Kriegers.
Cam
Unfortunately cam I'm probably in a slightly different situation to you as for me it's one or the other.
I wouldn't make weight with a 1.25 AND a tuner. So I'm at a bit of a fork. Either go with what I know or try a HV with a weight.-
Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
- Been thanked: 1 time
Just finished her tonight in the new stock- krieger 1.25 straight (the one I was having trouble with) and a 700gr stainless dampener/tuner. It can be moved or fixed into place. I gave the barrel 600 odd rounds before figuring out the action scope rail was loose. So its had a rechamber since it was looking good in the throat and now 29 inches. Last time I shot it with different loads it held about half x ring at 400m. Was rather impressed with it and that wasnt even fiddling with the tuner. Will do some tuning at 700m this weekend with it to get a load figured out.
Cam I swear Im not trying to copy you, but black with stainless just looks sexy!
-
Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
- Been thanked: 1 time
-
pjifl
- Posts: 883
- Joined: Fri Jun 17, 2005 12:15 pm
- Location: Innisfail, Far North QLD.
- Has thanked: 3 times
- Been thanked: 463 times
I see modifying and damping barrel vibrations as two distinctly different things.
I would expect a rigidly fixed mass to change the amplitude and frequency and nodal positions. But the vibrational energy would be the same. Well - it would gradually decay but over a longer timespan.
Some non rigid materials are good at reducing vibrational energy by converting it into heat fairly quickly. This dampens the vibrations.
But, for this mechanism to work, vibrations must already be present. The greater the amplitude of vibrations, the better the damping. Sure, the vibrations will be noticeably damped. Maybe the shooter will sense a different feel. But, I would expect there to be little or no damping until well after the bullet has left the barrel.
Peter Smith.
I would expect a rigidly fixed mass to change the amplitude and frequency and nodal positions. But the vibrational energy would be the same. Well - it would gradually decay but over a longer timespan.
Some non rigid materials are good at reducing vibrational energy by converting it into heat fairly quickly. This dampens the vibrations.
But, for this mechanism to work, vibrations must already be present. The greater the amplitude of vibrations, the better the damping. Sure, the vibrations will be noticeably damped. Maybe the shooter will sense a different feel. But, I would expect there to be little or no damping until well after the bullet has left the barrel.
Peter Smith.
Just to clarify if you can Peter -
Are you saying the fixed weights aren't really dampening vibrations - just modifying the frequency (I guess "slower"?) and amplitude ("larger"?) such that energy remains the same?
Adam- Nice way to ask a curly question for sure! I don't think anyone can give you a definitive answer as to which is better yet and you probably have to ask yourself do you want to experiment with it rather than an outright answer? Ultimately it will come down to the individual barrel quality more than the system between these two options. I have both and have seen remarkable results from both. I think the potential for the heavy weight on thinner barrel is to change significantly the tune as Peter outlined above (sorry I have been calling it "dampening") and can give you quite a different outcome to a straight taper stiffer barrel - of course the 32" versions have a slower frequency but larger amplitude vibration compared to short barrels as well but not to the same extent as a thinner barrel with muzzle weight. Both can be tuned to be accurate and both should have wide nodes. I have seen top level rifles in both configurations but theoretically (and seemedly in the real world) the weighted barrels should be slower frequency but larger movement.
There is of course another (potential) type of pulse here called the "P wave" and described in the OBT theory and Varmint Als website where the barrel opens up in a pulse down the barrel. when these waves hit the muzzle it is theoretically like a poor crown. Larger diameter barrels at the muzzle (whether it weight or just barrel diameter) should open up less than small diameter barrels such that "scatter nodes" may not be as severe - that is the theory at least.
Are you saying the fixed weights aren't really dampening vibrations - just modifying the frequency (I guess "slower"?) and amplitude ("larger"?) such that energy remains the same?
Adam- Nice way to ask a curly question for sure! I don't think anyone can give you a definitive answer as to which is better yet and you probably have to ask yourself do you want to experiment with it rather than an outright answer? Ultimately it will come down to the individual barrel quality more than the system between these two options. I have both and have seen remarkable results from both. I think the potential for the heavy weight on thinner barrel is to change significantly the tune as Peter outlined above (sorry I have been calling it "dampening") and can give you quite a different outcome to a straight taper stiffer barrel - of course the 32" versions have a slower frequency but larger amplitude vibration compared to short barrels as well but not to the same extent as a thinner barrel with muzzle weight. Both can be tuned to be accurate and both should have wide nodes. I have seen top level rifles in both configurations but theoretically (and seemedly in the real world) the weighted barrels should be slower frequency but larger movement.
There is of course another (potential) type of pulse here called the "P wave" and described in the OBT theory and Varmint Als website where the barrel opens up in a pulse down the barrel. when these waves hit the muzzle it is theoretically like a poor crown. Larger diameter barrels at the muzzle (whether it weight or just barrel diameter) should open up less than small diameter barrels such that "scatter nodes" may not be as severe - that is the theory at least.
-
pjifl
- Posts: 883
- Joined: Fri Jun 17, 2005 12:15 pm
- Location: Innisfail, Far North QLD.
- Has thanked: 3 times
- Been thanked: 463 times
Dampening is how quickly the vibrational amplitude (hence energy) decays. This decay is caused by internal 'friction' within the material where it flexes the most. Every material has a characteristic internal friction. We see (or hear) this when we strike a piece of steel and compare the 'ringing time' to that of cast iron or even lead. There is a fancy name for this 'internal friction' but that is unimportant.
During the short time a bullet stays in the barrel the vibration may be modified in character by a fixed weight but I would expect any dampening to be close to zero.
I was trying to compare this with what happens when a non rigid material is used like the rubbery blobs one sees on some barrels or if a weight is attached via a layer of rubber like material. I doubt these change the actual vibration much - certainly initially. Eventually, after many excursions of the barrel against their surface the rubber will flex back and forth and convert some of the vibrational energy to heat. This will increase dampening but it cannot do this until the vibrations have flexed the rubber material back and forth many times. In the 1 - 2 ms the bullet travels along the barrel I cannot see this amounting to much dampening.
Never considered a P wave scenario.
Armchair predictions are always suspect until proven, so if anyone wants to experiment go ahead. In any case, there may be some other beneficial effects.
During the short time a bullet stays in the barrel the vibration may be modified in character by a fixed weight but I would expect any dampening to be close to zero.
I was trying to compare this with what happens when a non rigid material is used like the rubbery blobs one sees on some barrels or if a weight is attached via a layer of rubber like material. I doubt these change the actual vibration much - certainly initially. Eventually, after many excursions of the barrel against their surface the rubber will flex back and forth and convert some of the vibrational energy to heat. This will increase dampening but it cannot do this until the vibrations have flexed the rubber material back and forth many times. In the 1 - 2 ms the bullet travels along the barrel I cannot see this amounting to much dampening.
Never considered a P wave scenario.
Armchair predictions are always suspect until proven, so if anyone wants to experiment go ahead. In any case, there may be some other beneficial effects.
Thanks Peter,
And for those that have not read this - it is worthwhile
http://the-long-family.com/shock%20wave ... nation.pdf
A very interesting theory that made a lot of sense to me at the time and do agree "fits" a lot of the observations.
So - other potential side benefits (theoretically) could be "holding" (perhaps even constricting slightly) the muzzle and reducing the effect of this "P wave".
There are others - such as torque and recoil reduction etc.
As Peter said there may be other (unexpected bonuses) and experimentation is the best way to make progress.
And for those that have not read this - it is worthwhile
http://the-long-family.com/shock%20wave ... nation.pdf
A very interesting theory that made a lot of sense to me at the time and do agree "fits" a lot of the observations.
So - other potential side benefits (theoretically) could be "holding" (perhaps even constricting slightly) the muzzle and reducing the effect of this "P wave".
There are others - such as torque and recoil reduction etc.
As Peter said there may be other (unexpected bonuses) and experimentation is the best way to make progress.
-
AlanF
- Posts: 7532
- Joined: Wed Jun 15, 2005 8:22 pm
- Location: Maffra, Vic
- Has thanked: 229 times
- Been thanked: 936 times
DaveMc wrote:...."holding" (perhaps even constricting slightly) the muzzle...
Has anyone noticed whether the constriction of these barrel weights causes copper fouling near the muzzle? I suspect that my barrel clamp causes a slight constriction. Are they fitted with a slight clearance that is taken up by the glue, or are they a very tight fit?
Alan
Most are fitted with glue and a tapered fit (although some are on turned down barrels and straight). I suspect the glue joint possibly does little to hold the barrel diameter (as the epoxies tend to give a little and by nature there is already a bit of tolerance) unless applied with heat or pressure (pressed or knocked on). Controlling this on a tapered fit would be an artform.
I have noticed no extra copper on mine but only have one and it is glued not under pressure.
I have heard one or two people suggest the barrel clamps may be restricting the barrel where we would not want to.
I have noticed no extra copper on mine but only have one and it is glued not under pressure.
I have heard one or two people suggest the barrel clamps may be restricting the barrel where we would not want to.
Menu
Newest members