Tuner info needed

[JohnsonGunsmith]

I would like to know more about tuners. What/who's design is doing the best? The atmospheric conditions have a lot to do with tuning, what devices are being used to read conditions? Brand names? What all conditions are these sensors required to read? Thank you I am new to Benchrest and am attempting to buy the best the 1st time as I am told that is the way to do it and save money in the long run. I know this will have a variety of answers and that is fine I just need pointed in the right direction.

 

[crb]

I just started in 07 and really made my biggest gains this year as far as group shooting. My suggestion is to get a top shelf 30BR rifle, buy some custom bullets, buy 200 preprepped cases, preload with 33.8 gr of H4198 and go enjoy yourself.

Save the tuner stuff for 5 years down the road [ if then ]. My current 30BR has a tuner but I never move it. The rifle can shoot small early in the morning and do the same thing late in the afternoon.

 

[Charles E]

Basically, tuners are a weight at the muzzle end of the barrel that change the barrel's vibration characteristics. So, for example, you could have a fixed weight, and the deflection of the muzzle would be reduced when the rifle is fired. In itself, that is (usually) an advantage. If you can adjust the weight, you can to some extent change the remaining characteristics of barrel vibration.

But for a moment, suppose the weight wasn't adjustable. Suppose further that your shooting technique was to use a single case and reload it at the bench as you shot your group. Under this model, the movable part of the weight, the "tuning," would be of far less value -- you can accomplish much of the same thing by by varying the powder charge. This is because a large part of "tuning a load" is controlling just where the muzzle is when the bullet exists the bore. You can control this by the amount of time the bullet spends in the barrel (charge variation) or by changing the vibration characteristics of the barrel (weight at muzzle).

Now you can argue -- and be right -- that changing the time in bore (charge weight) and barrel vibration characteristics (tuner) are not *exactly* the same, so using both techniques would improve groups/scores. In theory, that seems true. The problem is, (1) we don't understand *exactly* and *completely* how tuners work,and (2) your time and money are far better spent learning to read the conditions.

So the first reply in this thread, skip it for the time being, isn't bad advice. Lean how to tune a load, prove out your learning over some time, and then learn what a tuner can add. Almost nothing in benchrest should be used as an excuse for not understanding the fundamentals.

Aside from changing the vibration characteristics of a barrel, weight added can do one more thing: damp the vibrations. Rimfire shooters sometimes use a snubber -- a weight added to the barrel closer to the forearm. This weight is usually metal with a rubber insert. It is not tightened too much. We think, but do not know, that it absorbs some of the barrel vibrations.

Note that a tuner should (in theory, re Vaughn) be tight. essentially a part of the barrel, like the action. A snubber should be relatively loose. Some have tried two piece tuners where the weight portion (as opposed to the adjustment portion) is somewhat isolated from the barrel, in effect, combining both devices in a single one. They have had some success. No one I know has tested to see if the single device will perform as well as using two devices, each designed and constructed according to theory.

There are always compromises. The compromises here are weight and cost.

To directly answer your question, there is no best, because we do not understand the actions of tuners well enough. We do not have a complete theory which will *predict* results. What we have is empirical evidence that they work, which is a long way knowing exactly how they work (scientific predictive theory).

A bit on the notion of *buying the best.* You can't. Usually we don't know what is "best." When we do, It isn't for sale -- for example, the best barrel is the one on so and so's rifle, and he wont sell it. All you can do is to try and improve your odds of getting "very good" by using designs and manufacturers whose products consistently perform. The performance of each product can be mapped on a bell-shaped curve. What you want is products where the x-axis of that curve is quite short. Fortunately, the custom manufacturers who aim their products at the benchrest community most all have a short x-axis!

 

[Tony C]

Gene Beggs tuner is worth researching.

Tony C

 

[tim in tx]

pretty close charles,testing to date has shown we are dealing with 3 main factors in accuracy with tuning.[1] high frequency vibrations caused by firing pin drop,bolt slap,sear drop,case slapping the inside of your chamber and muti pieced tuners as well .these high frequency vibrations need to be dampened and directionally random shots is the effect on target. kind of like hitting your gun with a hammer right before you pull the trigger. since this vibration is a traveling vibration you just change the exit timing to get around the remaining high frequency vibrations or find the dead spot and put it at the muzzle as calffee has said where these vibrations would not add deflection.the problem with that theory is only the low frequency vibrations are dampened but the high frequency still causes deflection even in this dead spot of the muzzle.in testing i have eliminated most of my high frequency vibrations by tightening up my tolorances and going to a one peice barrel again on my rifles so there is not an issue in that respect . [2]low frequecy vibrations or natural vibrations so it has been said are basicly the vibrations remaining after the shot,shooting fast without dampining can give random shots as well.putting a couple of fingers on your barrel between shots can fix that issue especially if the gun is a ringer when you shoot it .and last but not least [3] not a vibration but more of vertical bending under recoil , a tuner or adjustable weight of any kind is basicly effecting this bending , but in jackies tuner killing the high frequency vibrations as well.the problem i have with that is that weight is still moving on the muzzle and not held firmly which could effect consistancy ,but it still seems to work for him . but a vertical bending of the barrel is what is comonly seen as vertical shots in the target and that is what a tuner changes. by adding weight to the muzzle you are slowing the swing down and adding more deflection at the same time,which is good only if you are on a upswing,in that respect the more the deflection the better. you can do the the same thing with powder adjustments and without a tuner to a point and with much less upswing of the barrel , the downside is a fairly narrow tune.that is what we know as of now .hope this helps sirs tim in tx

 

[Charles E]

Tim,

The usual problem we are tying to solve with tuners is vertical shot stringing. Just for the fun of it, new shooters -- and tuning device developers -- should remember Speedy Gonzales' advice, reprinted here:

http://www.6mmbr.com/verticaltips.html

Outside of load development, almost none of the things Speedy mentions will be helped by a tuner. One reason it is so hard to come up with a *predictive model* for tuners. By predictive model, I mean "if this happens, do this, and such and such will result."

An obvious example is if you know a bullet's drag (B.C.) and muzzle velocity, you can compute how many clicks to put on the scope to move from 100 to 1,000 yards. We don't have a similar predicting model for tuners, in part, because the core phenomena, vertical stringing, can have so many causes.

To his credit, Gene Beggs gave it a try. Remember the "Winter of Density Altitude?" The discussion raged all winter on BR Central. A lot of people were sure it would work for LV-weight rifles chambered in cartridges similar to the 6 PPC. The sale of devices that would measure density altitude skyrocketed that winter. I privately wished there were thousands of bechrest shooters, so come spring, I could sell short the stock of those companies who made them.

And of course, come spring, it turned out to not be the entire story, with no Paul Harvey in sight.

Try testing your ideas on return-to-battery unlimited rifles. Even go as far as Joel and I, and build rifles where the center of mass of the whole rifle is along the centerline of the bore. The first thing that will teach you is the geometry of the rifle matters, and any tuner that comes with specific instructions -- not those simply saying "move it until you get the best groups -- had better include geometry and weight of the rifle as a part of the instructions. Also case sizing, firing pin issues, etc. etc. There are just too many variables.

I still believe that a simple, unmovable weight on the end of the barrel, coupled with what I call a snubber, and load development will take you just as far.

I'd also be curious as to how many point-blank shooters use a tuner on their rail guns.

Charles

 

[jackie schmidt]

Charles, I have always believed that one of the nessessary components encorporated in a tuner is a snubber, much like myself, Gene Bukys, Charles Huckeba, and others use........jackie

 

[Charles E]

Hi Jackie,

Rimfire shooters have been using snubbers off and on since the 1930s. Now I'll be the first to allow that rimfire and centerfire are different animals, but there is a lot of crossover. Tuners were developed for CF, I believe -- the Browning Boss. But it was RF shooters who first picked them up in competitive benchrest. We CF shooters lagged in adopting tuners, because, we said, we could tune by changing the load.

In RF, snubbbers are placed much farther towards the breech than normal tuner placement - they seem to work better there. Maybe it doesn't hold true for CF, but as far as I know, nobody has even tried. I'm sort of ashamed to say that I've had a Henrich snubber sitting on the shelf for almost five years, and have never gotten around to testing it.

You, obviously, would be a good tester, far better than me. I still hope to get around to it, but in any case, two data points are always better. See the May 2006 issue of Precision Shooting for a test on using the Henrich snubber (RF), where Allan Hall did the shooting.

The ideal starting point would be, I think, according to the bit of theory we do have. The tuner should be solid when locked, and weigh at least 4 ounces. The snubber, like the Henrich, should have the somewhat loose attachment afforded by the rubber. Initial snubber placement 1 inch in front of the forearm. Leave the tuner alone, and move the snubber forward about an inch at a time. There should be several sweet spots. Pick one, then start adjusting the tuner.

Now, if the settings this way show improvement, and if the placement of the snubber is significantly behind the muzzle, we'd have evidence that the two devices are working on different parts of the barrel vibration problem, and combining them into a single unit will not work as well.

Of course, as always, any gains will pale beside learning to read the conditions.

 

[Boyd Allen]

My modest tuner experience was with one of Jackie's pre-snubber units and a Sims Deresonator. In my short and unscientific testing of where the Deresonator worked best, I tried it stretched over the tuner, and on the barrel, immediately behind the tuner. I also tried the tuner by itself. Of those options, behind the tuner seemed to work the best. I will add that the Deresonator did an excellent job of damping vibrations and weighed something like 1 1/4 oz. When tapping the barrel with a small wrench, loosely held, adding the Deresonator would change the sound from a longer "ting" to a very short "thump". The material is very gummy and soft, and is supposed to have better damping characteristics than Sorbathane. As to fit, Jackie's design seems to be a good one, with a full split and double clamping screws combined with a fine pitch thread of the maximum diameter. When my friend fitted it to my barrel, he cut the threads a bit too tight, with the split allowing the tuner to be started, and then used a buffing wheel to polish the threads till he had the tightest practical fit. This may make the more elegant machinists wince, but given the tooling available, it worked well. One more detail that may be helpful, this was a used barrel, with not much life left in it, and we did not have a way to flute it, so we stepped it to take off the weight that the tuner and Deresonator added (5 1/4 oz. if I remember correctly). It seemed to work well for that purpose. In going back to to the Sims web site, to check my spelling of their product, I discovered that the name has been changed. It is now called the Sharpshooter X-Ring. http://www.limbsaver.com/2010/products/firearms/xring_ecosafe_gun_oil.php#sharp
I have talked to shooters who have tried them and seen a noticeable improvement in accuracy on hunting rifles, not in every case, but often enough to be worth trying, given the cost.

 

[tim in tx]

charles sir ,only geometry you have to worry about to make tuners work is it has to have a lug ,or held below center some way[barrel block]. these theories do not apply to a rifle that is held on a centerline, as the forces are not offset so it is a tottally different movement.i am dependent on the lug to get the vertical motion going .you need to try these theories and then tell me that tuners are not universal , they are very universal and the only instructions needed are just put it on, crank it until it shoots tight and when it dont turn it some more until it does,but make notes of da or temp for your own individual formula .set it here for 85 degrees and set it there for 65 degrees,and turn it in when it heats up or turn out when it cools down thats pretty simple to do ,and works wonderfully even with .5 once weight. what gene says is exactly right i have tested his ways too. i know a gent that does very well with the da meter, and with genes style of tuner ,that is why genes tuners and butches tuners are pretty much standard equipment in 100 yd stuff.at least at the local club here in n. tx. weight doesnt matter for generally tuning a rifle.from a .5 to whatever will tune a rifle .you say your 1000 gun is centered on the axis of the bore so now you have no deflection whip or whatever then what?you have groups that are tottally dependent on having low es to be in tune.which never happens 100% of the time,so the agg can suffer from a single errant velocity . what i am saying is you must have some deflection or you could not repeatedly make a bullet go in the same hole of a different velocity.so just putting a non adjustable weight on a barrel even dampend is sheer guessing, the dampening part would work great if you have a sloppy bolt or loose fit brass or out of square lugs,etc , and the wrong weight could make it harder to tune by powder . how about this charles, to show you how universal these theories are as far as being predictable and with different barrel configurations i will predict what will happen on the next test coming up and let gene beggs confirm it. tim in tx

 

[Boyd Allen]

Tim,
As you undoubtedly know, being in the thick of things in Texas, some of the very top shooters in your part of the world, or in the case or Mr. Buckys, the whole world, choose to adjust their tuners when they are first mounted, and then lock them and leave them, tuning in the more "normal" manner from that point forward. As to the immateriality of weight, Bryn Boras (sp?) has reported that his Beggs tuner has no effect on his HV barrel, in contrast to his sporter, where it has been used to good effect. Because he has done well using a tuner in registered competition, we may infer that he knows something about how to successfully utilize one. This is not to say that a half ounce tuner cannot work, but I have never heard of one being used in any regestered competition. Where are these local 100 yard matches? Could you can and post some results from one. I curious as to the aggregates that are posted. Maybe we could learn something. Also, I believe that Gene Beggs' current theory of operation involves setting the tuner by looking at the vertical, not temperature, during the first match, and adjusting according to a temperature formula from that point forward. I believe that a reliable system that uses any combination of altitude, density altitude, temperature, humidity, or anything else that can be readily measured at a match, to allow a reliable preseting of a tuner, with abosolute confidence, has yet to be found. Or perhaps I have just not heard of it.

 

[tim in tx]

boyd ,i did say it incorrectly,i am speaking of adjustable weight,for example with a 5 ounce brake/ tuner and 1/2 once of weight that is adjustable it will change groups and correct vertical . with genes 3 once weights system behind the muzzle if the gun wont respond you can either slow down the bullet or recess the crown an inch into the barrel and then it will respond or you can add weight to make it respond but it can work with any contour,it just depends on where you are in the swing cycle and adding weight or taking away weight will put you in a spot where it will respond it is just more aparent on a slender barrel due to more flex. another example/ 2 barrels with same hv contour same cal same speed but one is 1 inch longer,1 responds with 3 ounces and one does not, what do you think is the issue ?then the 1 inch longer barrel is recessed to change up in bore timing and it then responds to tuning with 3 ounces just like the shorter barrel. with 3 ounces of adjustable weight i have a 7 mag that i can set reliably to temp and has been shot in registered competition and can keep it in tune,now i dont win much but it doesnt mean it isnt in tune , i am 100% sure it is in tune at any temp.point being now the winds are my only worry if i see vertical. try to search the denton match results ,i am not very good at posting links with this new format yet.but lot of them guys use beggs tuners and butches tuners and all of them shoot very well.i dont really know all of their names but one person that comes to mind using the density meter is ralph stewert but ralph is like jackie in that he wins a lot,he is just a great shooter as all the denton shooters are.they sure humbled me.i just cannot hold a 5 target agg like they do, tim in tx