Adding a fixed barrel weight.
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lewis reynolds
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- Location: sawyers gully
Adding a fixed barrel weight.
I am thinking of adding a weight to the front of my 284 shehane benchmark barrel. it is an extremely accurate barrel but seems to have a very narrow tuning window.i would like to try to broaden this window. What i would like to know is if anyone has any experience or done testing with them and how to mount them and if they should protrude forward from the crown, or finish flush and any ideas regarding overall weight? my rifle weighs approximately 9.3 kg.
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lewis reynolds
- Posts: 112
- Joined: Mon Mar 28, 2011 7:37 pm
- Location: sawyers gully
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Fergus Bailey
- Posts: 134
- Joined: Sun Jun 19, 2005 6:57 am
My knowledge of barrel tuners comes from BR, though I am slowly adding them to all my competition barrels.
I started using a tuner briefly in 2005 when they were made legal in the USA BR rule books. There was not much known about tuners at that time, although the knowledge base is much more extensive since then.
I initially started with a two piece tuner - essentially 2 nuts that bear down on each other to lock in place. This style of tuner is predominantly behind the muzzle, though a small portion does sit forward of the muzzle. I stopped using the break because I did not have the time to learn its nuances, but I was never entirely happy with it.
Since that time, a number of US BR competitors have used a tuner that largely sits forward of the muzzle, and this has become the predominant style used in BR. In fact at the last BR world championships, 5 of the top 10 shooters were using some form of what I would refer to as a "forward of the muzzle" tuner.
I have added this style of tuner to several rifles, and have seen an improvement on all the barrels. I am in the process of adding a tuner to more barrels based on my positive experience to date. From a relatively limited time using the different designs, the forward of the muzzle type seems to be the better option of the 2.
I started using a tuner briefly in 2005 when they were made legal in the USA BR rule books. There was not much known about tuners at that time, although the knowledge base is much more extensive since then.
I initially started with a two piece tuner - essentially 2 nuts that bear down on each other to lock in place. This style of tuner is predominantly behind the muzzle, though a small portion does sit forward of the muzzle. I stopped using the break because I did not have the time to learn its nuances, but I was never entirely happy with it.
Since that time, a number of US BR competitors have used a tuner that largely sits forward of the muzzle, and this has become the predominant style used in BR. In fact at the last BR world championships, 5 of the top 10 shooters were using some form of what I would refer to as a "forward of the muzzle" tuner.
I have added this style of tuner to several rifles, and have seen an improvement on all the barrels. I am in the process of adding a tuner to more barrels based on my positive experience to date. From a relatively limited time using the different designs, the forward of the muzzle type seems to be the better option of the 2.
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Brad Y
- Posts: 2181
- Joined: Fri Jun 26, 2009 8:21 pm
I have a 700gr adjustable tuner on the end of my shehane barrel. It was a dog of a thing to get into tune and I must admit now I have started getting some promising results. Just beware that if your close to 10kg already your tuner weight will be included in overall weight. Once I finish my load work I will put up some info of it.
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Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
Lewis
Send me a pm and I will get you my phone no.
When I get time I may do a story on my experience with barrel weights, come tuners.
Briefly, my idea was to dampen the barrel vibrations to widen the accuracy node and I got lucky. It is the mass that does the work. I now believe the adjustable part is not needed. Marty uses fixed tuners as a mass and we all know how that worked out...... he is no. 2 in the world.
I work in the power industry and we use vibration dampers on High Voltage power lines. These come in all sorts of configurations. I just took the simple design of a mass at the end of each span to dampen vibration.
Hope that makes sense
Cam
Send me a pm and I will get you my phone no.
When I get time I may do a story on my experience with barrel weights, come tuners.
Briefly, my idea was to dampen the barrel vibrations to widen the accuracy node and I got lucky. It is the mass that does the work. I now believe the adjustable part is not needed. Marty uses fixed tuners as a mass and we all know how that worked out...... he is no. 2 in the world.
I work in the power industry and we use vibration dampers on High Voltage power lines. These come in all sorts of configurations. I just took the simple design of a mass at the end of each span to dampen vibration.
Hope that makes sense
Cam
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williada
- Posts: 969
- Joined: Wed Jul 22, 2009 12:37 am
tuner
To Lewis and others, what you are trying to do is change amplitude of the barrel to broaden your tune window by adding the weight or extending your barrel and you are on the right track. I merely pass on what I have learned over a long, long time and would be happy for others to build on this knowledge.
One solution if you are seeking add a fixed weight to your muzzle would be to bore a piece of stainless in the lathe and taper the end attached to your barrel muzzle (if not a straight taper barrel), to be a push on, machine fit. I would use “Locktight” to permanently fix it. The reason I would not screw it or clamp it is because the barrel muzzle can be pinched tighter with grub screws and it doesn’t take much to induce a fouling issue or gas seal problem. It is this weakness I see in the one size fit all commercial tuner tubes with threaded movable weights.
A few shooters went through a craze about 20 years ago with comments that they wanted to increase the sight radius on Fullbore rifles, when in fact the ones in the know were following Obermyer’s experiments with amplitude. Obermyer’s tubes on thirty calibres were about 5-6 inches long and their weight slowed the wave length. Modern tuners behave the same way but most have moveable weights. Most importantly, Obermyer also thought he established a relationship between the internal diameter of the added weight which extended past the muzzle and accuracy. The reason he gave was, the gas turbulence interfered with boat tail bullets in the tube and upset them. His solution was to bore out the extender tube to an optimum size. My memory is a bit hazy as to what size. But if you are using a .284 for instance, the bore size of the tuner tube would need to be different and this part needs to be applied to the modern threaded tubes with moveable weights. I tried to validate these experiments on bore size by making successive tubes wider to compensate for the increasing bore size to eliminate the weight variable. This was a lot of work. I firstly started with a tube bored out to .75” about 6 inches long and successively cut it back longitudinally to establish a weight that gave reasonable groups with factory ammunition. At this stage only relative group size mattered. Having established a fundamental weight, I then proceeded to play with bore sizes and external diameters to keep this weight constant. At the time I convinced myself it was better. I think I settled 0.86’’ for .308 barrels, as I tossed this stuff into the scrap bin a long time ago. The downside is that you need a long rifle case. Weight limits of the rig have to be within the rules.
With all that said I use a Begg’s type tuner and realize how itty bitty movements of the tuning discs really matter and the other approaches were too agricultural. The overall weight of my tuner is about 3 ozs although heavy shorter barrels may require more tuner weight. I favour threading the barrel itself for the discs to move along, with no extended sleeve. Firstly, because Obermyer’s experiments were too time consuming to setup; secondly, because I think a proper crown should be allowed to work in its own right without the imposed atmosphere conditioning of an extended tube past it; and finally because the rifle balance point which is critical to control recoil is not too far forward. Not to mention the difficulty of cleaning the crown and the slops left in a fixed tube. If you are fastidious then cleaning a tube could give you a margin but it depends on how much time you want to spend. Tuners work. The week before David Rich went to the USA a couple of years ago with the Australian Team, his rifle was not performing with a new barrel made to team specks. The only change we made was to tune it properly with a tuner, something he was not familiar with. He won the individual championship and then went on to win the New Zealand Queens. These guys hold a better group than most F classers, but the knowledge is transferable.
Barrels with small nodal windows are best accommodated by paying strict attention to case headspace and neck tension if you are reloading. I favour adjusting the tuner once a good load is worked up for fine tuning. Old habits die hard, as I still adjust powder to maintain constant velocity for different seasons and I can’t be bothered altering position on the mound in order to change a tune. It becomes Catch 22 for us seniors as our technique is a bigger challenge than the tune.
David
One solution if you are seeking add a fixed weight to your muzzle would be to bore a piece of stainless in the lathe and taper the end attached to your barrel muzzle (if not a straight taper barrel), to be a push on, machine fit. I would use “Locktight” to permanently fix it. The reason I would not screw it or clamp it is because the barrel muzzle can be pinched tighter with grub screws and it doesn’t take much to induce a fouling issue or gas seal problem. It is this weakness I see in the one size fit all commercial tuner tubes with threaded movable weights.
A few shooters went through a craze about 20 years ago with comments that they wanted to increase the sight radius on Fullbore rifles, when in fact the ones in the know were following Obermyer’s experiments with amplitude. Obermyer’s tubes on thirty calibres were about 5-6 inches long and their weight slowed the wave length. Modern tuners behave the same way but most have moveable weights. Most importantly, Obermyer also thought he established a relationship between the internal diameter of the added weight which extended past the muzzle and accuracy. The reason he gave was, the gas turbulence interfered with boat tail bullets in the tube and upset them. His solution was to bore out the extender tube to an optimum size. My memory is a bit hazy as to what size. But if you are using a .284 for instance, the bore size of the tuner tube would need to be different and this part needs to be applied to the modern threaded tubes with moveable weights. I tried to validate these experiments on bore size by making successive tubes wider to compensate for the increasing bore size to eliminate the weight variable. This was a lot of work. I firstly started with a tube bored out to .75” about 6 inches long and successively cut it back longitudinally to establish a weight that gave reasonable groups with factory ammunition. At this stage only relative group size mattered. Having established a fundamental weight, I then proceeded to play with bore sizes and external diameters to keep this weight constant. At the time I convinced myself it was better. I think I settled 0.86’’ for .308 barrels, as I tossed this stuff into the scrap bin a long time ago. The downside is that you need a long rifle case. Weight limits of the rig have to be within the rules.
With all that said I use a Begg’s type tuner and realize how itty bitty movements of the tuning discs really matter and the other approaches were too agricultural. The overall weight of my tuner is about 3 ozs although heavy shorter barrels may require more tuner weight. I favour threading the barrel itself for the discs to move along, with no extended sleeve. Firstly, because Obermyer’s experiments were too time consuming to setup; secondly, because I think a proper crown should be allowed to work in its own right without the imposed atmosphere conditioning of an extended tube past it; and finally because the rifle balance point which is critical to control recoil is not too far forward. Not to mention the difficulty of cleaning the crown and the slops left in a fixed tube. If you are fastidious then cleaning a tube could give you a margin but it depends on how much time you want to spend. Tuners work. The week before David Rich went to the USA a couple of years ago with the Australian Team, his rifle was not performing with a new barrel made to team specks. The only change we made was to tune it properly with a tuner, something he was not familiar with. He won the individual championship and then went on to win the New Zealand Queens. These guys hold a better group than most F classers, but the knowledge is transferable.
Barrels with small nodal windows are best accommodated by paying strict attention to case headspace and neck tension if you are reloading. I favour adjusting the tuner once a good load is worked up for fine tuning. Old habits die hard, as I still adjust powder to maintain constant velocity for different seasons and I can’t be bothered altering position on the mound in order to change a tune. It becomes Catch 22 for us seniors as our technique is a bigger challenge than the tune.
David
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Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
-
Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
Re: tuner
williada wrote:
with. He won the individual championship and then went on to win the New Zealand Queens. These guys hold a better group than most F classers, but the knowledge is transferable.
David
Dave, that is a bold statement if you are talking TR.
Cheers
Cam
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DenisA
- Posts: 1526
- Joined: Wed Nov 09, 2011 7:00 pm
- Location: Sunshine Coast, QLD
How long in general are the powder charge accuracy nodes that forum members are finding with their 30" long, non weighted barrels?
How much longer does a barrel weight make them?
I'm sure they're all different for different barrels and components but it would be interesting to hear a few examples.
My .284 is running in the middle of a node that extends over .3g of ar2213sc. The most accurate part of the node is at the hotter end, but the trouble is the next .1g opens the group and drops the P.O.I a little. I want to stay safely in the middle to allow for slight changes in temperature, fouling and components.
Would a barrel weight simply extend that node and make it less susceptible to these temperature and components inconstancies?
How much longer does a barrel weight make them?
I'm sure they're all different for different barrels and components but it would be interesting to hear a few examples.
My .284 is running in the middle of a node that extends over .3g of ar2213sc. The most accurate part of the node is at the hotter end, but the trouble is the next .1g opens the group and drops the P.O.I a little. I want to stay safely in the middle to allow for slight changes in temperature, fouling and components.
Would a barrel weight simply extend that node and make it less susceptible to these temperature and components inconstancies?
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johnk
- Posts: 2211
- Joined: Sun Sep 07, 2008 7:55 pm
- Location: Brisbane
Denis,
On the basis of what other match rifle shooters & I have been doing over the last 1-12 years, a moderate back of barrel weight only modifies the occurrence of the sweet spot, not it's duration. By that I mean that we load for the highest possible velocity with good spread (& maybe SD) characteristics, then fiddle the weight until it groups appropriately, and that can be a tedious process on occasion but arguably less tedious than the alternative. However, over time, we have an expectation about what load might result in that occurring. Remember that we are shooting over a relatively short distance spread (200 yards), not the 700 that occurs with Queens distance F class.
My F standard barrels work without the need to barrel tune & maybe that's because I'm still using about the same charge of AR 2206 that I did a decade ago.
I have Shadetree front of muzzle (mostly) tuners on my two F open barrels, which I use to modify barrel characteristics to suit the various distances. The 6BR only needed a couple of marks on the jam nuts to tune it from shorts to longs, The 30-284 is still a work in progress.
I look at tuners as being an alternative to tweaking seating depth & neck tension for performance. The aim of the game is still to achieve a load with single digit velocity spreads & the capability to be extracted in one piece on the firing point; my way is an alternative method to arrive at the third desirable outcome - accuracy.
John
On the basis of what other match rifle shooters & I have been doing over the last 1-12 years, a moderate back of barrel weight only modifies the occurrence of the sweet spot, not it's duration. By that I mean that we load for the highest possible velocity with good spread (& maybe SD) characteristics, then fiddle the weight until it groups appropriately, and that can be a tedious process on occasion but arguably less tedious than the alternative. However, over time, we have an expectation about what load might result in that occurring. Remember that we are shooting over a relatively short distance spread (200 yards), not the 700 that occurs with Queens distance F class.
My F standard barrels work without the need to barrel tune & maybe that's because I'm still using about the same charge of AR 2206 that I did a decade ago.
I have Shadetree front of muzzle (mostly) tuners on my two F open barrels, which I use to modify barrel characteristics to suit the various distances. The 6BR only needed a couple of marks on the jam nuts to tune it from shorts to longs, The 30-284 is still a work in progress.
I look at tuners as being an alternative to tweaking seating depth & neck tension for performance. The aim of the game is still to achieve a load with single digit velocity spreads & the capability to be extracted in one piece on the firing point; my way is an alternative method to arrive at the third desirable outcome - accuracy.
John
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Cameron Mc
- Posts: 1089
- Joined: Tue Jun 28, 2005 10:55 am
- Location: Darling Downs SE Qld
DenisA wrote:
Would a barrel weight simply extend that node and make it less susceptible to these temperature and components inconstancies?
G day Denis (Champ)
The major benefit I have found with the barrel weight is the extended node. Once I have found the sweep spot I know I can go +/- 0.5g powder and stay well inside the 6 ring if I do my part. This is a major benefit when changing to different lots of powder ... burning rates can vary, lot to lot. This comes into play as you go back to the longer ranges. I have found 300 to 500yds is no big deal with some of the small variations....... but the barrel weight still helps accuracy.
For myself the barrel weight really made things easier for the world champs. As my good wife was also shooting I had to get 4 barrels all singing in tune. With 4 Kriegers I was able to use one lot of identical cartridges with brilliant accuracy. This made loading much easier, faster and importantly less prone to error. All 4 used 52g 2209 with 180vld's in OZ. In the US I dropped 0.5g because we were at high altitude. I did not adjust the tuners. I guess a little luck may have been on my side too. If I need to make anymore tuners they will be "fixed", not adjustable. I don't see the need. I can't see how you could fine tune a barrel at 1000yds...too many variables.
Cheers
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DenisA
- Posts: 1526
- Joined: Wed Nov 09, 2011 7:00 pm
- Location: Sunshine Coast, QLD
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