Tuners some info.

Alinwa
I think the earth just quit revolving around its rotational axis.Did Francis say he is using a tuner? and that Bill Calfee was right years ago?:D

Pacecil
The proof is on the targets not in the theory.The tuners weight is important and they do work.Until you try one your the person using theory.
Lynn aka Waterboy
 
Gene Beggs said:
Good point Ray! :eek: I'll bet you're right. :D

We are making good progress; aren't we? :D

Later

Gene Beggs
Click to expand...

Gene,
At the last Riverbend club 100/200 group match my HV 30BR with my metal stock and one of Hal's tuners was low on 3 targets, 2nd on 2 more targets, had one of the three 1's shot at 100 and was entirely capable of winning the match except that I suck as a group shooter [ some now solved technical issues didn't help ]. This is only the rifle's 2nd match and first group match and I was astounded at actually being competitive in a group match. I did manage to be 2nd at 100 even after shooting a .6 on the 4th target.
I can't wait for next month's score match ;)
 
Watch the flags :)

crb said:
Gene,
At the last Riverbend club 100/200 group match my HV 30BR with my metal stock and one of Hal's tuners was low on 3 targets, 2nd on 2 more targets, had one of the three 1's shot at 100 and was entirely capable of winning the match except that I suck as a group shooter [ some now solved technical issues didn't help ]. This is only the rifle's 2nd match and first group match and I was astounded at actually being competitive in a group match. I did manage to be 2nd at 100 even after shooting a .6 on the 4th target.
I can't wait for next month's score match ;)
Click to expand...



No Text
 
What happened is that my 'highly tinkered with' :rolleyes: joystick rest was a bit sticky in the cold temps we had at the match. It took me a while to get the crosshairs lined up for the second record shot of the day [ we start at 200 ]. In the mean time the wind reversed and gusted about the time I pulled the trigger. The result was a 2.355 first group of the day and no chance to win. I was low for next target and second on the third target :puke:
On the 4th target the wind was crazy for a LONG time. I then had some cases hang up in the drop port [ a problem now taken care of ]. I was closing the bolt on the 5th record shot at the 15 second warning = 1.75. This also happened on the 4th 100 yd target = .600 .
End result was the gun that should have won was 5th.
Earlier this year I decided to sell my 6mm's and shoot this 30 in both the group matches and the score matches. Now that I have seen this rifle's potential I am a happy camper.
Long live metal stocks and tuners !!!!! hahhaaahhaaahha:D

ETA: Part of the thought process that lead to the decision to shoot this rifle in both group and score matches was the idea of not even shooting the group matches as I have never done worth a heck in a group match but have always been competitive in the score matches. There was no RFBR match last Saturday so I went to the group match as a shakedown for the rifle and load with my new Cheek 112's. ;) I was actually shocked and a little bit discombobulated to be behind a rifle doing the biz.
 
Last edited:
Butch Lambert said:
Gene,
I believe our beyond the barrel tuners weigh 5.4oz.
Butch
www.shadetreeea.com
Click to expand...


Butch, I'm familiar with your tuner design, I was there during much of the testing, which was conducted in my tunnel. It works and works well. It is a well made piece of equipment offered at a reasonable price. If I remember correct, the original prototype weighed 6 ounces. Your website lists the weight as 6.4 ounces. Whatever the actual weight, the ShadeTree tuner is unquestionably heavier than mine which weighs exactly 4 ounces. The main difference is that your weight rings mount on an adapter beyond the muzzle; mine are screwed directly onto the barrel behind the muzzle.

IMHO, the rings of my tuner are easier to adjust. They have four 5/32" holes drilled in the outer radius and two little tommy bars are used to tighten. The weight rings of the Shadetree are knurled on the outer radius which helps the shooter get a grip on them with his fingers. The advantage of this is that no tools are required; however, it could be a problem for someone with a bit of arthritis. You could make a setup using one of your Bridgeports and a dividing head and drill four 5/32" holes in all your rings lickety split! This would give the shooter the option of using the tommy bars. ;)

For a heavy varmint rifle, your tuner may be the best choice. Your threads are 32 tpi; mine are 28. Your rings have etched lines and numbers, while mine have only one reference mark. If you were to reverse the rear ring of your tuner and engrave a reference mark, it would greatly simplify adjustments. Yes, your threads are slightly different but will work fine. .036 movement per revolution vs., .031. :rolleyes: We're not talking about micrometer-fine adjustments here, only eight clock positions. :)

Butch, I would not hesitate for a moment to install one of your tuners on a customer's heavy varmint rifle. Some folks drive Fords, others prefer Toyota or Chevy. I'ts nice to have a choice; isn't it? :D

FWIW

Gene Beggs
 
crb said:
Gene,
At the last Riverbend club 100/200 group match my HV 30BR with my metal stock and one of Hal's tuners was low on 3 targets, 2nd on 2 more targets, had one of the three 1's shot at 100 and was entirely capable of winning the match except that I suck as a group shooter [ some now solved technical issues didn't help ]. This is only the rifle's 2nd match and first group match and I was astounded at actually being competitive in a group match. I did manage to be 2nd at 100 even after shooting a .6 on the 4th target.
I can't wait for next month's score match ;)
Click to expand...


That's a good report Ray! :D Hang in there.

Gene Beggs
 
Gene Beggs said:
Mike Ezell
Click to expand...
If you do not clean between relays, you can trust the barrel to deliver consistent velocities and stay in tune. :cool:
Gene Beggs[/QUOTE]

The above checks out with me. Years ago after a new barrel change and a modest 10 shot break-in, I went to an indoor range and fired 80 rounds until the group started to open up.:) Well...that's more than enough to go through one yardage in Hunter without cleaning. I just clean between the 100 and 200yd match aggs. Works for me...so far.

Now if I can only convince the rifle to shoot where I want it...instead of where I point it.:rolleyes:

virg
 
Gene Beggs said:
See my post number 144.

Gene Beggs
Click to expand...

Gene,
Excellent, we are on the same page. Now here is something else to think about - there are three ways that barrel motion can affect where a bullet strikes the target:

1) The barrel can be at a different height when the bullet exits. This effect doesn't amount to much, since the amplitude of vibration of a stiff BR barrel is only in the 0.010" range.

2) The barrel's upward/downward velocity is imparted to the bullet when it exits. A difference in barrel velocity from one bullet to the next will cause dispersion. This effect is also in the 0.010" range for a group with decent ES, not too important.

3) The angle of the muzzle determines the launch angle for the bullet. This the important one.

If you look closely at Al's simulations, you see that the centerfire muzzles with tuners have reached a peak in height and are on their way down and accelerating when bullets exit, so effects 1 and 2 are both working in the wrong direction to compensate for different bullet exit times. Only effect 3 is working in the right direction. As the muzzle is dropping, its angle is whipping upward, which counteracts effects 1 and 2 AND compensates for some of the vertical dispersion due to differences in bullet velocity.

According to the simulations, tuners aren't perfect yet. Muzzle angle needs to change faster to eliminate vertical. A barrel with reduced stiffness, particularly toward the muzzle might work better (see Al's barrel contour called "Grandpa's inch").

Also, forearm stiffness may be more important than we realize. This would be something easy to try with your clamp-on forearm. With the clamp near the breech, you could try strips of different materials and thicknesses as the forearm. Something light and moderately flexible might amplify barrel motion just the right amount to completely eliminate vertical. Did you try anything like this during your development?

Cheers,
Keith
 
mks said:
If you look closely at Al's simulations, you see that the centerfire muzzles with tuners have reached a peak in height and are on their way down and accelerating when bullets exit, so effects 1 and 2 are both working in the wrong direction to compensate for different bullet exit times.
Cheers,
Keith
Click to expand...
You must have looked at a different Varmint Al site.
upward-downward-slope.png

SUMMARY.... For the reader who doesn't want to wade through all the discussion here is a summary of what a tuner can do to correct for small variations in muzzle velocity from round to round. The Muzzle Projection Curve shows where the muzzle is pointing at a 100 yard target while the rifle is being fired. The most important aspect is the curve is where the muzzle is pointing at the time the bullet exits the muzzle.

Improving accuracy by compensating for small variations in muzzle velocity.

Smaller Groups Left of the Peak - UPWARD SLOPE:
Higher velocity shots exit early while pointing lower at the target but drop less in reaching the target.
Lower velocity shots exit later while pointing higher at the target but drop more in reaching the target.
Counteracting combination. Good.

Larger Groups Right of the Peak - DOWNWARD SLOPE:
Higher velocity shots exit early while pointing higher at the target and drop less in reaching the target.
Lower velocity shots exit later while pointing lower at the target and drop more in reaching the target.
Bad additive combination. Bad.
Click to expand...
 
Gene B.
You are right on the weight. Must have been the Arrogant Old Bastard beer that Shilen fed me at the Feed we had last night before the Swap Meet.
Butch
 
mks said:
Gene,
Excellent, we are on the same page. Now here is something else to think about - there are three ways that barrel motion can affect where a bullet strikes the target:

(GB) No Keith, we are still not on the same page; not even close and it took me quite a while to realize it. Believe it or not, we are talking about two different things. You and Varmint Al are talking about barrel motion; what the barrel/muzzle does before bullet exit. I'm talking about the sine wave that appears ON THE TARGET.

1) The barrel can be at a different height when the bullet exits. This effect doesn't amount to much, since the amplitude of vibration of a stiff BR barrel is only in the 0.010" range.

2) The barrel's upward/downward velocity is imparted to the bullet when it exits. A difference in barrel velocity from one bullet to the next will cause dispersion. This effect is also in the 0.010" range for a group with decent ES, not too important.

3) The angle of the muzzle determines the launch angle for the bullet. This the important one.

If you look closely at Al's simulations, you see that the centerfire muzzles with tuners have reached a peak in height and are on their way down and accelerating when bullets exit, so effects 1 and 2 are both working in the wrong direction to compensate for different bullet exit times. Only effect 3 is working in the right direction. As the muzzle is dropping, its angle is whipping upward, which counteracts effects 1 and 2 AND compensates for some of the vertical dispersion due to differences in bullet velocity.

According to the simulations, tuners aren't perfect yet. Muzzle angle needs to change faster to eliminate vertical. A barrel with reduced stiffness, particularly toward the muzzle might work better (see Al's barrel contour called "Grandpa's inch").

Also, forearm stiffness may be more important than we realize. This would be something easy to try with your clamp-on forearm.

(GB) Keith, you may be confusing my forend design with that of Shelley Davidson's Tinker Toy. My forend is simply a three inch wide milled aluminum block that bolts directly to the barrel. In one sense of the word the barrel IS the forend. With my forend design, the only option one has for experimentation is the position fore and aft on the barrel, which I have found to be unimportant except for rifle balance.

With the clamp near the breech, you could try strips of different materials and thicknesses as the forearm.

(GB) On his Tinker Toy rifle, Shelley Davidson used two round tubes that did indeed attach near the breech of the barrel with clamps. His barrel was free-floating while mine is rigidly supported by the forend block and front rest.

Something light and moderately flexible might amplify barrel motion just the right amount to completely eliminate vertical. Did you try anything like this during your development?

(GB) No.

Cheers,
Keith
Click to expand...



Keith, my comments appear in bold preceeded by (GB)

By this point in our discussion, we have lost about 99 percent of our readers. Most have probably said, "Aw to 'ell with it; I'm not interested in all that technical stuff, it's too complicated for me!":mad: And they're probably right. It isn't necessary to get this deep into academics in order to use a tuner and shoot well. The top benchrest shooters in the world aren't interested in this stuff. They spend their time looking for hummer barrels, superman bullets and practicing. :D

Later,

Gene Beggs
 
Last edited:
Boyd Allen said:
On the rise, where the curve flattens out, just before the peak, compensates by letting the faster dropping slower rounds exit at a higher angle than the flatter trajectoried faster ones that exit at a lower angle. Varmint Al's graphs are a great learning aid, and unique in my experience. Learning new stuff is fun!
Click to expand...



Boyd, here we are talking about the sine wave that appears on the target. See my post #161

Yes, learning new stuff is fun. :)

Later,

GeneBeggs
 
Gene,
On the left of the graph we see." Muzzle projection to 100 yard target". It would seem that he IS referring to something that would directly influence the relative elevations of bullet holes. As you know, turners change the frequency of this motion so that the bullets can exit at a more advantageous point in the barrel's cycle. The timing of the muzzle elevation cycle with bullets' exits is what produces what we see on the target. I think that the only difference is that the graphic shows the cause and the target shows the effect.
 
MUZZLE & TUNER AT EXIT.... This picture shows the orientation of the muzzle at the time of bullet exit, approximately 0.00092 seconds. It is pointing upward and the projection to the 100 yard target is still climbing. The projection stays near this position for about 0.0001 second. See the charts below.

Keith
I think you are misreading table 2.You want the barrels muzzle climbing at the time of bullet exit and table 2 shows the droop caused by gravity coupled with the rise for each velocity.The faster shots appear lower because the barrel hasn't risen as much as the slower shots due to more barrel time.The muzzle is still rising.
Waterboy aka Lynn
 
Keith,
When I had one of Jackie's earlier tuners to a well worn barrel, its weight combined with that of a Sims Deresonator totaled about 5 1/4 oz. The rifle was already at the limit, and I intended to shoot it in a match. Not having the desire to invest in fluting the barrel, we stepped it. The front cylinder was the major diameter of the tuner thread, 15/16, and was continued to the rear to a point where the step up to the original contour was about .050 (.100 diameter difference). From that point, at the top of a ninety degree step a cylinder was cut back to the point that a step of the same size as the first one was created. From that point the original contour was left as it was. Because of the constant taper, the two cylindrical sections were the same length, a little over 6 1/4", and the weight removed exactly matched that added at the muzzle. I have no idea whether the reduction in stiffness helped the tuner work better, but that old middle of the road at best barrel won its last match at 200 with a .291. I thought that it shot better all weekend, and needed less load adjustment. I decided to leave the tuner alone and change the powder as it got hotter after lunch. I understand that there are at least a couple of very successful Texas shooters that do the same thing. With the tuner, stepped barrel, and ugly rubber donut it was quite a sight. Nevertheless, given the improvement, if I had a lathe, or a larger budget, all of my barrels would have had tuner threads, Deresnoators and steps. To paraphrase Forrest Gump, ugly is as ugly does.
 
Of interest to me at least

Is the reverse taper used on RF barrels. I am just getting into this but I was told that barrels are tuned on RF Sporters by taking small amounts off the reverse taper portion until "Tune" is achieved. Has anyone experimented with Reverse Tapered CF barrels?
 
You must log in or register to reply here.
Back
Top