Tuners some info.

mks said:
Gene,
If I remember correctly, the Davidson forend clamped between the action and the barrel like a recoil lug. What I was thinking of was something more like your design that clamps on the barrel. The way it would be different would be that it would clamp near the action, and the plate would extend farther forward. Two clamp halves and a attached plate 3" wide and about 16" long. One could try different plates, say wood, fiberglass and aluminum, of different thicknesses to see if any improved tuning.

There is some suggestion that this might work in that some shooters tune by how far they place the front of the forend past the front rest. Varying this position changes how forend motion gets transmitted to the muzzle.

Just another wild idea:),
Keith
Click to expand...


Keith, maybe your idea is not so wild after all. Check out post number 179 by Landy.

Gene Beggs
 
lynn..For best accuracy do you want the bullet to exit the muzzle on the upswing or downswing?
According to Varmint Al's work it should be on the upswing.

Is the muzzle deflecting downwards when the bullet leaves? and why is it deflecting downwards?
It will depend on the barrel length and velocity or time in barrel for the particular bullet and barrel you are asking about.

Does adding or changing the weight of the tuner make all the difference in the world? or does it really matter as long as you make weight?
Whether you make weight has no relation to what a tuner does or does not do, so your question makes no sense.

Does moving the tuners weight in or out a thread change the amount of weight as seen by the muzzle? In other words can you put a 1 pound weight on your outstretched arm and get the same affect as placing it on stick 10 feet away?
As you move the weight out you increase the moment about the muzzle. So, in this fashion I think it would meet your definition of "weight seen by tuner". Moving the weight out has somewhat the same EFFECT of adding weight.

Did Varmint Al think tuners were a plus or a waste of time?
V.A. didn't express his opinions. He simply gave you the results of his analysis, and let you make up you own mind.

If you can put two bullets through the same hole at 100 yards with a 8 grain variation in the powders charge weight(300 Ackley) is that huge variation in grouping ability associated with the weight of the tuner or is there some other factor we are not seeing?
That is ZERO variation in the group so there is nothing having effect!


If I am getting 3/4 of a bullet hole worth of vertical at 100 yards using a 308 bullet and turn my tuner 1/4 turn and get one hole groups what caused that to happen?
That's a .157 change in group size. If you could duplicate this and thus produce this as an average over a number of groups then I would say you have effected the change by your tuner.

If it is repeatable and it is why is that?
Obviously, it must be because of whatever change you made....or by some change that occurred that you weren't aware of.


On your guns with tuners what are you seeing with regards to group sizes while adjusting your tuner and is it in front of or behind the muzzle? and what if any difference can we expect to see between the two positions?
All the tuners I've tested have been out in front of the muzzle. I could never discern enough of a difference in accuracy that I could definitely say it was caused by the tuner. Maybe my guns or my ability to shoot them is just not at a high enough level! As to expected difference between the two positions I would expect some difference but it may be very hard to separate quantity of weight from position of the weight.

Gene beggs... Pacecil, were you there? Did you witness the experiment? In the real world, things don't always turn out as they do on paper and in computer generated models. Let's not nitpick the numbers to death; who cares? Regardless of how much the barrel actually grew, we can all agree it grew some; how's that?
Who cares! Well, I think most people who read this forum care! Your response that "it grew some" "who cares" is typical of too many people. You will take a number, any number, as long as it agrees with your theories or experiences! Your right I didn't see how he did his experiment, but I have the results of thousands of "experiments" done over the last few hundreds of years by thousands of testers that proved his was in error!

Whoa, whoa; hold on there Smokey, I can give you some numbers you can rely on! And I can tell you exactly what happens when you give my tuner a half turn, and I can tell you exactly how far it moves and I can tell you exactly where to place it when the ambient temperature increases to X degrees. I don't just throw out numbers and statements based on speculation; what I say, I have proven in the real world in actual conditions. I have come to have great respect for Varmint Al and his work but regardless of what his computer generated models show, I know for fact what happens in the real world.
Okay, lets see the numbers!

Bull! I never "sorta' changed" anything I said. I assure you, it IS changes in air density (weight) that causes our rifles to go out of tune, not barrel temperature and the reason you do not understand this is because you have never piloted highspeed aircraft. You have no appreciation for the enormous force of air at mach 2.7.
Okay, I'm no pilot and you are. Lets see you back up your theory or statement with some numbers or some test results.

Finally, Gene, you don't seem to understand whether I shoot or not, whether I'm a pilot or not, or whether you shoot or not, has nothing to do with what we are talking about here. We are talking about natural laws, as we understand them, that apply to most everything in this universe. Quit making this out as "you verses me"! I'm not telling you it's YOUR ambient air that's affecting the bullet's travel, or even that it's YOUR tuner that's affecting accuracy. Let's try and keep this from becoming so personal!
 
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Gene Beggs said.....
George Ulrich found there was considerable growth in length of a 24 inch barrel when heated to 120 degrees F. (How's that Pacecil?)

George's initial measurements showed a .030 increase in length with approximately a 50 degree increase in barrel temp. Some have questioned the .030, claiming that according to calculations, it should be much less but they were not there and I doubt they have actually duplicated the setup that George used and actually measured the increase in length. In the real world, things don't always work out like they do on paper and in computer generated models.

George said he stood the 24 inch barrel on a granite surface plate and made his measurements with precision instruments, both temp and length. George is a very competent and knowledgeable tool and die maker and I would be very cautious about questioning his results. Regardless of how much the barrel grows in length, we can all agree it grows SOME. (How's that Pacecil?)
Okay, his tests proved that the thermal coef. of expansion for the steel in his barrel was .000024 inch/inch/deg F. Never seen steel that high but I'll assume his is. If the steel in your barrels is same then I'm sure you will want to use this figure when ever you have to.
 
Pacecil,
We were going good till you got to the bit about "That is ZERO variation in the group so there is nothing having effect!"
With 8 grains difference in powder charge, the slower load had to have the muzzle pointing higher on the target than the faster one. Assuming that the scope was not touched and a common point of aim, wouldn't something have had to caused that to happen?
 
You don't get it...

pacecil: "Finally, Gene, you don't seem to understand whether I shoot or not, whether I'm a pilot or not, or whether you shoot or not, has nothing to do with what we are talking about here. We are talking about natural laws, as we understand them, that apply to most everything in this universe. Quit making this out as "you verses me"! I'm not telling you it's YOUR ambient air that's affecting the bullet's travel, or even that it's YOUR tuner that's affecting accuracy. Let's try and keep this from becoming so personal!"

Sure, the rest of the universe is important, but what we're trying to learn and apply from this forum IS: How does it apply to shooting!

Jim
 
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pacil, I'll throw a challenge at you. If you are provided an airline ticket to Gene's tunnel and 1 night in a hotel would you have balls enough to go?
Butch
 
Originally posted by Pacecil "All the tuners I've tested have been out in front of the muzzle. I could never discern enough of a difference in accuracy that I could definitely say it was caused by the tuner."

(GB) Pacecil, you say all the tuners you have tested have been out in front of the muzzle. How much did they weigh? What was the thread pitch? Did you try turning the tuner to different positions? Did the groups change in size as you tested each of the eight clock positions?


(GB) Pacecil, when I said, "I assure you, it IS changes in air density (weight) that causes our rifles to go out of tune, not barrel temperature and the reason you do not understand this is because you have never piloted highspeed aircraft; you have no appreciation for the enormous force of air at mach 2.7" You answered,

Pacecil quote: "Okay, I'm no pilot and you are. Lets see you back up your theory or statement with some numbers or some test results."

(GB) I have already given you the numbers such as;

1. What my tuner weighs. 4 ounces.

2. What thread it uses. 28 tpi. .036 per revolution.

3. How far can it be out of tune. Half of a turn; .018

4. If the rifle is perfectly in tune at 50 degrees, what must you do to keep it in tune when the temperature reaches 60 degrees? Turn the tuner "IN" a quarter turn or .009 toward the breech.

Pacecil, you asked me to back up my theories with numbers or test results. I've given you what I consider to be the important numbers; what others do you want? As far as backing up my theories with test results, I cannot provide you with documented, hard copies of my tests but I can sure SHOW you if you will come to the tunnel or if we can get together at a range somewhere.



Pacecil quote: "Finally Gene, you don't seem to understand; whether I shoot or not, whether I'm a pilot or not, or whether you shoot or not, has nothing to do with what we are talking about here.

(GB) Sorry; I disagree. I think who we are, what we are, and what we have done has MUCH to do with what we are talking about and how we perceive things.

When one has LIVED in an environment for many years and his very life depended on his understanding the laws of physics that govern that environment, I think he is better qualified than someone who understands it only in theory. There is nothing like experiencing something first hand.


Pacecil quote: "We are talking about natural laws, as we understand them, that apply to most everything in this universe."

(GB) Yep, I agree! :D I sometimes refer to them as God's laws and they do not apply to MOST everything in this universe; they apply to EVERYTHING and EVERYONE!


Pacecil quote: "Quit making this out as "you verses me"! I'm not telling you it's YOUR ambient air that's affecting the bullet's travel, or even that it's YOUR tuner that's affecting accuracy. Let's try and keep this from becoming so personal!"

(GB) Okay Pacecil, I'll try. :)

Later,

Gene Beggs
 
Lynn said:
Keith
Al is giving you the whole cycle in his examples.He lists were you want the muzzle going for best accuracy and that is up.

If you look at the model of my rifle on his website it appears that the barrel is too long and that the accuracy is suffering or on the down swing.That same rifle shot 3 world records as it was modeled.

The muzzles downward velocity is caused by the muzzle being pointed up.
Lynn aka Waterboy
Click to expand...

Lynn,
I think you are referring to the graph that Vibe posted, which is muzzle projection. Yes, one wants the muzzle projection rising. Not that it makes a lot of difference, but I tend think of the muzzle angle following the downward velocity. If a flexible rod is accelerated on one end, the opposite end tries to follow, but the mass of the rod causes it to bend. Because the displacement of the opposite end lags, the angle is created. Not a big deal, the two effects are connected. I am afraid it may be typical of a wide range of CF BR rifles, short and long range, that the muzzle is moving downward when bullets exit. Not to worry, though, if the muzzle angle is rising fast enough to compensate.

Not trying to make excuses, but it is not easy modeling rifles and getting the simulations to match experiments. Probably the most difficult part is coming up with the material properties of the stock, especially for a composite stock. You have probably noticed that getting the simulations to match for Esten's rifle involved making the modeled stock less stiff. In the end, the agreement was pretty good. With some data for matching, I expect the computer model for your rifle could be improved, too.

Cheers,
Keith
 
Keith,
Hypothetical question...What effect does stock stiffness have on where the bullet exits on Varmint Al's graph? If everything else is held constant, would a stiffer stock move curve peak to the left, right, or neither? What about the sharpness or duration of the peak?
Boyd
 
Butch Lambert said:
pacil, I'll throw a challenge at you. If you are provided an airline ticket to Gene's tunnel and 1 night in a hotel would you have balls enough to go?
Butch
Click to expand...


Hey Butch, that's a terrific idea! :D I'll sure chip in my share of Pacecil's expenses. How 'bout the rest of you? Would you be willing to contribute to this little project? It would be in the best interests of everyone and it would be a lot of fun. I promise, I'll take good care of Pacecil and I assure him and everyone else, I'm not one to take advantage of or make fun of anyone. :D

Ask anyone who has been out to shoot with me in the tunnel including Wilbur, if I'm the big, bad, hairy tunnel monster that some think I am. :rolleyes: :) Will Rogers once said,

"I never met a man I didn't like."

I wouldn't go that far but I will say, "I have met very few men I didn't like." :D

Pacecil, come on out. We'll go get some good BBQ and Mexican food, maybe have a cold beer or two, tell some jokes, do a little shootin' and get to know each other. That way you can decide for yourself whether or not I'm for real and know what I'm talking about. What do you say? :D

Later,

Gene Beggs
 
IndianaJames said:
pacecil: "Finally, Gene, you don't seem to understand whether I shoot or not, whether I'm a pilot or not, or whether you shoot or not, has nothing to do with what we are talking about here. We are talking about natural laws, as we understand them, that apply to most everything in this universe. Quit making this out as "you verses me"! I'm not telling you it's YOUR ambient air that's affecting the bullet's travel, or even that it's YOUR tuner that's affecting accuracy. Let's try and keep this from becoming so personal!"

Sure, the rest of the universe is important, but what we're trying to learn and apply from this forum IS: How does it apply to shooting!

Jim
Click to expand...


(GB) Jim, you're not the first to remind me of this and I'll do my best to confine my discussions to shooting, but I would like to say something in my defense.

Those who have a background in flying will tell you that bullets and airplanes have a lot in common. When trying to get a point across it is sometimes helpful to use analogies and relate to other disciplines. Know what I mean? :)

Gene Beggs
 
Gene
Do you have a railgun or some kind of machine rest in use at your tunnel? I ask because with a typical 1000 yard lightgun at 17 pounds it is easy to lose the tuners affects if your not capable of producing good groups.
With a unlimited gun or rail Pacecil would more easily see the opening and closing of the groups as the tuner is moved.
I'll chip in $100 as well.
Waterboy aka Lynn
P.S. Don't feed him any mexican food until after you leave the confines of your tunnel.:p
 
Boyd Allen said:
Keith,
Hypothetical question...What effect does stock stiffness have on where the bullet exits on Varmint Al's graph? If everything else is held constant, would a stiffer stock move curve peak to the left, right, or neither? What about the sharpness or duration of the peak?
Boyd
Click to expand...

Boyd,
Soften up the stock and the curve shifts to the right, similar to adding weight at the muzzle. The curve gets a little broader, too. You can see both cases on the Esten rifle page.

Keith
 
To Boyd Allen, you asked
We were going good till you got to the bit about "That is ZERO variation in the group so there is nothing having effect!"
With 8 grains difference in powder charge, the slower load had to have the muzzle pointing higher on the target than the faster one. Assuming that the scope was not touched and a common point of aim, wouldn't something have had to caused that to happen?
I have to admit I didn't quite understand what Lynn was describing. I see now he was describing V.A. analysis of a barrel of some length, a particular barrel time, and a specific velocity spread. For any particular combination of these variables there will be a range at which the trajectories cross. If that is what is happening in Lynn's example then I repeat: I'm not sure I can say any thing, such as tuning, can be given credit for this. It's just a circumstance that occurs. What more can I say?
 
Lynn said:
Gene
Do you have a railgun or some kind of machine rest in use at your tunnel? I ask because with a typical 1000 yard lightgun at 17 pounds it is easy to lose the tuners affects if your not capable of producing good groups.
With a unlimited gun or rail Pacecil would more easily see the opening and closing of the groups as the tuner is moved.
I'll chip in $100 as well.
Waterboy aka Lynn
P.S. Don't feed him any mexican food until after you leave the confines of your tunnel.:p
Click to expand...



Lynn, I no longer own a rail gun. I had a nice Jay Young rail for about four years and it was a fine piece of equipment but I never did enjoy shooting unlimited where you shoot eight, ten shot groups at 100 one day and the same at 200 the next day. Cecil Tucker bought the rail and in turn sold it to Dr. Ken Terrel and I lost track of it after that.

I have not put a tuner on a rail gun although I have been asked to do so. With the heavier, straight barrels in use on the rail guns, I would think you would need a much heavier tuner than mine. The barrels are usually 1.450. Maybe Jackie Schmidt could tell us more about that.

Don't worry, my two Sporters are plenty accurate to demonstrate the sine wave and tuner phenomena to Pacecil. Thanks for volunteering to help; I hope he takes us up on the offer.

Later

Gene Beggs
 
Gene commented...
Pacecil, when I said, "I assure you, it IS changes in air density (weight) that causes our rifles to go out of tune, not barrel temperature and the reason you do not understand this is because you have never piloted highspeed aircraft; you have no appreciation for the enormous force of air at mach 2.7"
Gene, I got it, you were a pilot! But the "enormous force of air at mach2.7" has almost nothing to do with what is being discussed here. I have to ask what it has to do with the slight change in the force required to push denser air out of the barrel ahead of the bullet? Explain to me the mechanism of how the slight change in pressure in the barrel ahead of the bullet has any significant effect on barrel vibration.

On another subject; I don't want numbers describing dimensions of tuners or how you recommend people adjust their tuners. I want some numbers showing how much the average group size changes as you run your tests with tuners. Tell us how average size of a number of groups (not just a few groups!) changes with ambient conditions and tuner adjustments.
 
pacecil said:
Gene commented...
Pacecil, when I said, "I assure you, it IS changes in air density (weight) that causes our rifles to go out of tune, not barrel temperature and the reason you do not understand this is because you have never piloted highspeed aircraft; you have no appreciation for the enormous force of air at mach 2.7"

Pacecil quote: "Gene, I got it, you were a pilot!"

(GB) Pacecil, let's forget about me being a pilot; sorry I mentioned it.

Pacecil quote: "But the 'enormous force of air at mach 2.7' has almost nothing to do with what is being discussed here.

(GB) On the contrary; it has almost everything to do with what we are discussing here.


Pacecil quote: "Explain to me the mechanism of how the slight change in pressure in the barrel ahead of the bullet has any significant effect on barrel vibration."

(GB) I'm not talking about the weight of the atmosphere having anything to do with barrel vibration; it is the weight of the atmosphere and its effect on in-bore elapsed time. Warmer, lighter air presents less drag to the bullet as it accelerates; less drag means quicker acceleration, quicker acceleration means less in-bore time and the bullets begin to exit the muzzle early. We can correct for this by reducing the load slightly or if a tuner is installed, by turning the tuner 'IN' by the required amount. If you cannot understand this, there is no need for me to continue.

Pacecil quote: "On another subject; I don't want numbers describing dimensions of tuners or how you recommend people adjust their tuners. I want some numbers showing how much the average group size changes as you run your tests with tuners. Tell us how average size of a number of groups (not just a few groups!) changes with ambient conditions and tuner adjustments."
Click to expand...

(GB) Nah,, I don't think so. :rolleyes: I've already wasted enough time with you. :mad: Don't bother directing more questions my way; this conversation is over.

Gene Beggs
 
Good for you Gene

a very unsophisticated man in the neighborhood I grew up in, when faced with someone like this would say to him " you know so much you don't know nothing". I have found a number of folks over my lifetime who fit into that catagory.
 
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