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Thread: SD and Barrel Harmonics

  1. #31
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    Quote Originally Posted by Joe Salt View Post
    Boyd if I'm reading this right, I think that is what I'm trying to find! The load that will work in all conditions. Once I get there its shoot what you got!

    Joe Salt


    Joe, you will never find a load that will work in all conditions; at least not in benchrest. Oh sure,,, if you have a load that has the bullets exiting just before the top stop of the muzzle as it is on the upswing, the load window will be wider than the one at the bottom. But if you want to stay right on top of the tune, you must be able to compensate for increases in temperature by changing the load or adjusting a tuner. For some good information on this, study Rod Brown's article in the March issue of Precision Rifleman entitled, "Tuning With a Tuner."

    Also, carefully review Boyd's post above. He knows what he's talking about.

  2. #32
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    Gene like I said you and boyd are the scientists, I'm the Rube Goldberg in this stuff, but sometimes it works. Gene about mirage I always thought of putting two scopes on a rifle is this what you were saying. But I thought of having one pointed a 50 yards and the other at 1000 so the mirage wouldn't make as much of a difference as what you were seeing at 1000! This on the same line.

    Joe Salt

  3. #33
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    http://optimalchargeweight.embarqspace.com/#

    This is the method I have been trying to duplicate @ 100yds. The emphasis is om harmonics of the barrel in relation to the charge weight. You all probably are familur with the method and have discarded it.

  4. #34
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    Quote Originally Posted by ekp View Post
    http://optimalchargeweight.embarqspace.com/#

    This is the method I have been trying to duplicate @ 100yds. The emphasis is om harmonics of the barrel in relation to the charge weight. You all probably are familur with the method and have discarded it.
    His fundamental premise is seriously flawed, so everything that is built on that flawed premise is faulty.

  5. #35
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    Quote Originally Posted by XBBR Shooter View Post
    His fundamental premise is seriously flawed, so everything that is built on that flawed premise is faulty.

    Is this the prevailing view of the community?

    Can you elaorate?

  6. #36
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    Quote Originally Posted by ekp View Post
    Is this the prevailing view of the community?

    Can you elaorate?
    The prevailing view of what community??? Beginning shooters think it is OK... but they are always looking fr an easy way to get their loads to shoot. But they lack the ability to evaluate it to see if it really works, or if they just settled.

    Any "system" that claims to give you perfect (or best) shooting solutions must be repeatable - id est, the same results over and over and over and over...

    If you do "OCW" test targets, and repeat them with the same loads, so that you have a bunch of the same tests - mark then "A", "B", "C"... and then give the group of targets to someone that was not involved with the shooting... and ask them to evaluate the groups, they will not come up with a consistent result.

    Further... if you repeat the tests, you do not get the same results.

    And, statistically, if a rifle has a potential of 1" group size at 200 yds, and you fire a shot, then increase the load by 0.3 grains, the second shot can be above or below the first shot, depending on where in the statistics the shot fell. You could repeat only those two loads over and over, and NEVER get the same results... that is NOT what a true system does.

    And, he says, "7. The primer brand you choose is entirely up to you. Use magnum primers only with magnum chamberings, as their added pressure may distort the OCW conclusions on standard chamberings. One exeption [sic] here would be with low density loads, as I believe that magnum primers improve ignition consistency in loads where the powder only fills 85 percent or less of the case."

    This not true, and reflects a lack of basic knowledge and experience in loading. Magnum primers do not produce more pressure, they produce a longer heat profile because of non-explosive additives... sometimes this might give more pressure, but sometimes it produces less pressure.... but to state that magnum primers will distort any results, reveal a basic lack of knowledge of loading - if magnum primers make it impossible to develop reliable groups, then how do one explain that many shooters use magnum primers in standard chamberings with excellent results.

    But this is what it really is all about...

    He is in the long distance load developing business... "Email me and I will develop your load from my keyboard."

    "Because of increasing demand (likely driven by the rising cost of reloading components), I'm now offering a one-on-one consulting service to personally assist you during your OCW load development process. Are you tired of getting those inexplicable "flyers" in your groups when you know that you didn't do anything wrong? Have you done ladder tests ad nauseum and you still haven't found a consistent load recipe? Is your load recipe so sensitive to minor changes that even a primer swap blows your accuracy? Would you like to learn how to make your cold, clean bore shot touch the rest of the group? Then keep reading...

    I've counseled hundreds of shooters over the years by email and internet forums to help them find "the" load for their rifle and application. While these encounters have been quite successful (don't take my word for it, google search my name and "OCW" and see for yourself), written interaction does have its limitations. In literally dozens of cases I can remember finding out that a handloader had overlooked obvious hinderances to accuracy--and this we sometimes learned only after he'd spent a couple hundred bucks on components and range trips. Although many folks have become quite profficient at interpreting OCW targets, I still see that many are not. This means that simply shooting an OCW test is only part of the accuracy equation--you also need to properly interpret the data. Another concern is that we see folks adjusting the OCW process and "improving" it, sometimes by shooting at longer ranges than are prescribed, and/or by failing to shoot in round-robin fashion, or adding shots or taking shots away... All of these steps will work against you in the end.

    Why hire a consultant?

    First and foremost, you will save money. Very likely lots of money. If you'll be honest with yourself and carefully add up the cost of bullets and powder and primers and worn out brass and trips to the shooting range, you might be surprised just how much that magical load you finally arrived at has actually cost you. In a recent case, a man who had spent over 300 dollars chasing an accurate load for his .243 Winchester was led to a sub MOA load recipe in less than 20 shots.

    I have compiled a database of handload information over the years that will allow me to steer you toward good combinations for your intended purpose--and away from bad ones. This alone will save you a considerable amount of money right from the start. Ballistics techs at the major bullet and powder makers don't always know what combinations work best. And like most handloaders, they tend to follow the age old "hunt and peck" method of load development, so any ideas you do get will have come from such processes.

    Finally, there are many basics that some of us forget when it comes to shooting accurately. It simply takes too long to go over each and every one of these issues when we're interacting by email and forum posts alone. Often, we need phone consultation to really get to the bottom of what is going on.

    If you choose to enlist my help for your load development endeavor, you will avail yourself of the following:

    Absolute privacy. Your name and information will not be shared by me for any reason unless you specifically grant me permission to share your target photos and/or testimony.

    Personal contact by phone on three to four occasions. In our initial conversation we'll discuss your rifle and scope combo, the purpose which you're using the rifle and load for, what components you may already have on hand which could work for you, and a sensible accuracy goal. In follow up phone conversations, we will discuss your targets (which you will send to me by email). We'll interpret the data, and consider seating depth adjustments that may improve your accuracy even more.

    Email contact, continual. You can follow up at any time by email if you have further questions about your load and its performance. We'll plan to stay in touch long after we've gotten the load working for you.

    A load that works. We will not stop until you're happy with the load you have. And during the process, you will learn much that will help you with other loads in the future.

    ------------------------------------------------------------------------------------------

    The cost of my service is a very modest 45 dollars, which you can pay by credit card or paypal. That's less than a pound of powder and a box of bullets. And if you consider your time worth anything at all, factor that in as well. You have my promise that you will save time and money, and on top of that you'll arrive at a load recipe that will get all of the potential from your rifle.

    Money back guarantee. In the unlikely event that we are unable to arrive at an acceptable load recipe for your rifle, I will gladly refund your 45 dollars, and you'll be no worse off than where you began.

    If you have any questions, or if you are interested in my services, email me----> "danielnewberry@gmail.com"

  7. #37
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    Quote Originally Posted by Joe Salt View Post
    Gene about mirage I always thought of putting two scopes on a rifle is this what you were saying? Joe Salt


    No, what I was referring to is a separate, fixed-reference scope mounted to the bench. Its purpose is to detect 'slow mirage' the kind that permanently displaces the target image causing one to aim at the wrong spot.

  8. #38
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    Quote Originally Posted by Boyd Allen View Post
    ... As far as the desired timing of bullet exit, going back to Varmint Al's unique and excellent work, according to his research, and calculations, the best place for bullets to exit, on the barrels primary rise and fall (shown as where it points on a target) is just before it peaks and starts to descend. In this part of the curve, as the elastic limit is approached (my interpretation ) the curve flattens indicating a reduced change per unit of time. ...
    It seems to be hard for people to get away from the "tune to the peak" concept. So hard that many, like Boyd (I don't mean to pick on you), just can't quite let it go and are now saying "just before the peak." In reality, the peak is unimportant. What we want is for the muzzle angle in the vertical plane to be increasing at just the right rate so that slow bullets are launched at a higher angle and hit the target at the same point as fast bullets. The necessary muzzle angular velocity can be calculated from external ballistics, though you will need a calculator that includes muzzle angle, which is not common. For a 30BR with muzzle velocities of 3012 and 3046 fps (these velocities were chosen for no other reason that they are from one of Varmint Al's simulations), I found 53 degrees per second to tune for 100 yards. (The optimal speed is different for other yardages.) I think this is in the ball park, since Geoffrey Kolbe measured 100 degrees per second to tune a rimfire at 50 meters. http://www.border-barrels.com/articl...g_a_barrel.htm

    We also want the muzzle to have zero angular velocity in the horizontal plane. Horizontal muzzle angular velocity causes horizontal dispersion on the target, and there is no way to compensate for it. As we try different loads, tuner settings, etc., we may find a window where vertical angular velocity is just right, but we have significant horizontal velocity, so we get horizontal dispersion. This, I think, is what is interpreted as a wind sensitive tune. In reality, wind has nothing to do with it. It's just that barrel harmonics plus wind add up to more horizontal dispersion that we expected. Or we may find a window where horizontal velocity is near zero, and vertical velocity may or may not match the optimum. This is interpreted as a wind insensitive tune, when it is really just the nulling of barrel harmonics that reduced horizontal dispersion.

    My $0.02,
    Keith
    Last edited by mks; 04-26-2013 at 06:00 PM. Reason: Corrected yardage.

  9. #39
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    Quote Originally Posted by mks View Post
    It seems to be hard for people to get away from the "tune to the peak" concept. So hard that many, like Boyd (I don't mean to pick on you), just can't quite let it go and are now saying "just before the peak." In reality, the peak is unimportant. What we want is for the muzzle angle in the vertical plane to be increasing at just the right rate so that slow bullets are launched at a higher angle and hit the target at the same point as fast bullets. The necessary muzzle angular velocity can be calculated from external ballistics, though you will need a calculator that includes muzzle angle, which is not common. For a 30BR with muzzle velocities of 3012 and 3046 fps (these velocities were chosen for no other reason that they are from one of Varmint Al's simulations), I found 53 degrees per second to tune for 100 yards. (The optimal speed is different for other yardages.) I think this is in the ball park, since Geoffrey Kolbe measured 100 degrees per second to tune a rimfire at 50 meters. http://www.border-barrels.com/articl...g_a_barrel.htm

    We also want the muzzle to have zero angular velocity in the horizontal plane. Horizontal muzzle angular velocity causes horizontal dispersion on the target, and there is no way to compensate for it. As we try different loads, tuner settings, etc., we may find a window where vertical angular velocity is just right, but we have significant horizontal velocity, so we get horizontal dispersion. This, I think, is what is interpreted as a wind sensitive tune. In reality, wind has nothing to do with it. It's just that barrel harmonics plus wind add up to more horizontal dispersion that we expected. Or we may find a window where horizontal velocity is near zero, and vertical velocity may or may not match the optimum. This is interpreted as a wind insensitive tune, when it is really just the nulling of barrel harmonics that reduced horizontal dispersion.

    My $0.02,
    Keith
    With acknowledgement to XBBR , his contribution and I do see his point, was not the premise of OCW to try to eliminate horizontal dispersion and then adjust the vertical with seating depth. I am not looking for a perfect system but everyone has a system of load development and I chose to try this one. Maybe the gentleman's real goal is to sell his services but that is the American way.

  10. #40
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    I don't know where you get your information. I have never written of tuning to the peak of the curve. The reference that I made was to Varmint Al's work that seems to indicate that the best area on his "where the muzzle is pointing on target" curve was just as I said, for the rifle loads and caliber that he was using as an illustration. Again, you have written that I a reluctant to let go of a position that I have never taken or written. If you are going to someone as an example, at least get your information correct. Evidently you have confused what someone else has written for what I have. As far as the rest of it goes, your idea of calculating the desired angle seems to be solid, and corresponds to thoughts that I have had but did not follow through on as well as you evidently have. I will count that as useful information for further study and consideration.

  11. #41
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    I'm going to take a different tack here..... on the "harmonics" issue.


    This will be utterly boring to some, to those I invite you, "don't read"

    Until I had in my hands a TRULY ACCURATE RIFLE I had absolutely no clue why my results were what they were. I wore out barrels "working up loads" using every method imaginable. My rabbit trails had rabbit trails on their rabbit trails.

    Then Art Cocchia built me a BR rifle. Actually, he built TWO identical rifles for myself and my friend with 7 barrels, 3 of them in "BR chamberings." With these rifles I learned some things but the STRANGEST I ever did see was that day on the marge of Lac Le Barge when I screwed a barrel on (22BR) and made a little round hole at 200yds, and then another one, and another one, and when I changed the load THE HOLE MOVED..... And it changed shape and it got bigger/smaller. And when the wind puffed the hole turned into a caterpillar, and sometimes a duck or a turtle.... but that's another story...

    And then the next day when I took my friend to show heem, I DID IT AGAIN! And again.... and HE did it..... and so on....

    without boring everyone with stories, my point is, "harmonics" as a useful tool only apply to ACCURATE platforms,

    IMO

    I can't imagine learning anything "harmonic" on a 1moa or even a half moa rifle.

    An ACCURATE rifle shoots a "5-shot one hole group" ALL THE TIME, it's just the shape of the hole that changes. From harmonics. With an ACCURATE barrel you can SEE THE WIND, and you can see harmonic effects.



    But I digress......


    I was at a seminar where Jim Borden illustrated his and Doc Jackson's "sine wave tuning" using barrel harmonics. I've still got the videotapes....and he spoke of graphing group centers on a horizontal line, (Jim does this in a 'double-blind' setting to minimize human action) how as the charges are gradually increased the group centers went up and down as a sine wave, essentially showing the barrel wagging up and down. But as I set and watched I wondered how many people in the audience realized that all the up and down movement was INSIDE the typical group! What I'm saying is, harmonics are subtle, half-inch-out flyers AIN'T HARMONICS! Of course flyers still happen, butterflies still fly in Japan, but they're rare and hopefully accounted for by something in the field of view....





    Observe the picture somewhere in this post. I took the pic during a workup section and posted it here on BRC to illustrate the view through a then-new 45 Leupold and to all you PPC/BR shooters here I must apologize because this IS NOT a short-range BR workup. I was testing a 6X47L shooting 108gr VLD's at around 3250fps......YES there's a lot of air showing but these ain't 68gr bullets, I think it still illustrates my point.

    I hope anyways


    Click image for larger version. 

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    Astute observers will notice some three shot and some five shot groups. Some observers may see WHY some of them are five shots...

    Anyway, I didn't change my scope settings, nor was I actually graphing a sine wave here..... but you will see that the better groups are forming in a different place than the others. And furthermore, if you could read the notes on this workup you'd see that the lower groups were going faster.

    Harmonics.

    ONLY visible because this IS an extremely accurate rifle. (For a VLD gun) This setup will eat 30's at 600yds. And if I ever get a chance at a 300yd Group Match.... and if'n it's windy....


    But again,





    I digress







    LOL

    al

  12. #42
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    I do learn a lot from this discussion. If developing a load for a sub moa or moa rifle the horizontal changes with the loads what then is the cause if not harmonics. In loads I have worked up I do see a pattern develop with increments of .2 or .3 depending on case capacity. Using a Nosler manual a lot of my picks are pretty close to theirs. Having worked in R&D in a lab I do know the value of repeatability. I also know the difference in field testing and lab results. Like most people I try to grasp any information out of what my field testing is telling me. When developing loads for a hunting rifle I probably try to put a too fine a point on it. Currently my .270 is giving me fits.

    This has been a helpful discussion.

    Thanks to all who have participated

  13. #43
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    ekp,

    I may have muddied the waters....

    A lot of the dispersion you're seeing IS from random vibrations in the system.

    RANDOM vibration.

    "Harmonics" are nodes or areas, even nulls, of ORDERED vibration in this system.

    It takes a really tight system to see the effects of these harmonic isolations. And to keep them ordered and usable. And their effects are small.

    al

  14. #44
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    Your mentioning your having problems finding a load for a .270 reminded me of the very first thing that I wrote that was published, in Precision Shooting, a one page letter asking why some barrels do not shoot BT bullets nearly as well as FB, that the editor turned into a short article. I had spent some time working with a friend's commercial FN Mauser in that caliber, and had found that it had a distinct preference for FB bullets. Of course with their advantage in BC a lot of shooters are drawn to BTs, and may struggle mightily to attain their accuracy goal, and if they do not try a FB, may never get there. ( This whole discussion was about factory barrels.) Answers tended to refer to tight and loose spots in barrels that did not shoot them well. In any case, my little piece elicited quite a response, to the extent that it was mentioned in 5-6 articles that followed in various issues of the same magazine. Evidently I was not the only one that had come across this phenomenon. My only reason for mentioning it here is that your mention of the caliber reminded me of that experience. The other thing that it reminded me of is that although 4831 filled the case a little better, I believe that I got better results with 4350, this with 130 grain bullets, although it has been so long that I couldn't swear to anything except the rifles preference for FBs. Good luck with yours.

  15. #45
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    Quote Originally Posted by Boyd Allen View Post
    I don't know where you get your information. I have never written of tuning to the peak of the curve. The reference that I made was to Varmint Al's work that seems to indicate that the best area on his "where the muzzle is pointing on target" curve was just as I said, for the rifle loads and caliber that he was using as an illustration. Again, you have written that I a reluctant to let go of a position that I have never taken or written. If you are going to someone as an example, at least get your information correct. Evidently you have confused what someone else has written for what I have. As far as the rest of it goes, your idea of calculating the desired angle seems to be solid, and corresponds to thoughts that I have had but did not follow through on as well as you evidently have. I will count that as useful information for further study and consideration.
    Boyd,
    Sorry, I shouldn't have offered you as an example of the entire evolution of the concept, but only the "just before the peak" idea from post #27. I will try to be more careful.

    My main point remains that where the shots are relative to the peak is immaterial. It matters only that they are on the upslope. In fact, because velocity typically decreases as the peak is approached and goes to zero at the peak, there is reason to say that being near the peak is not good.

    In support of this, the best spot on the upslope in Al's simulations still does not provide enough angular velocity to put the shots in the same hole. Being farther from the peak may be better. Or it may take different stocks and barrel contours. There is still work remaining to figure out how to get full "positive compensation" (Kolbe's words, which seem to fit well) for vertical, as well as to integrate horizontal dispersion into the model.

    Cheers,
    Keith

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