SD and Barrel Harmonics

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 ;)


6X47L workup.jpg


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
 
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
 
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
 
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.
 
Boyd Allen said:
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.
Click to expand...

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
 
I think that we can agree on the desirability of being some where on the up slope, and possibly that the placement may vary with the application. This page was the basis for my statement. http://www.varmintal.com/alite.htm , ann on this page http://www.varmintal.com/atune.htm ,near the bottom, under the subheading "AVERAGE VELOCITY BULLET" he says that he believe that optimal timing would have the average velocity bullet in a group exiting just before the peak.
 
Boyd Allen said:
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.
Click to expand...

I have been working with a 98 Custom built by W A Sukalle of Phoenix Arizona. Built 12/31/47. It is a beautiful rifle with great wood. I am in love with the rifle but am having a heck of a time to get it shoot 1 inch or under at 100. The bore is immaculate. I refuse to believe it is the rifle and have been busting my back to get it to shoot. For some reason it likes to copper foul vary easily. The bore does not show any tool marks. I fire lapped it to see if that would help. Working with a 98 magazine requires me to seat a far distance from the lands. I even order Hawk round nose to be able to seat closer. They shot miserably. I have had some luck with Winchester Power Points which are flat based. I have just tried some Nosler combined techs because of the Lubalox coating to see if that helps the fouling problems. I also have been working mostly with H4831SC because that seems to be everyone's powder of choice. At the range today I managed a ~3/4 inch group strung verically with 55.3gn of aforementioned powder with 130gn CT Nosler bullets. I have no faith that these results are repeatable. My 308 VLS or 223 Rem can shoot sub moa groups all day long but this 270 seems very fickle.
 
I would absolutely expect the Sukalle rifle to shoot between 1moa and 2moa and would be very surprised, would find it hard to believe in fact, to hear of it doing better.

IMO the build should be capable of 1.5moa on a given day and not wander more than 4 inches through the year.

al
 
I'ma' try sumpin..... a friend emailed me a better picture of the picture, I'll try to attach it from my email.

If I do it right it might blow up???

al-luddite-inwa


XXXXX-6X47L workup.jpg
 
alinwa said:
I would absolutely expect the Sukalle rifle to shoot between 1moa and 2moa and would be very surprised, would find it hard to believe in fact, to hear of it doing better.

IMO the build should be capable of 1.5moa on a given day and not wander more than 4 inches through the year.

al
Click to expand...

Would you hunt with this rifle? Someone did free float the barrel and glass bed the recoil lug and tang area of the action.
 
ekp said:
Would you hunt with this rifle? Someone did free float the barrel and glass bed the recoil lug and tang area of the action.
Click to expand...

Absolutely I'd hunt with it :) It's as accurate as 90% of the hunting rifles on the planet. It's a 350yd gun. At that range it'll group 5 inches.
 
ekp said:
I happened upon this thread and I thought it made good reading regarding the OCW method.

http://www.shootersforum.com/ballistics-internal-external/64349-ocw-load-development.html
Click to expand...


I have read that a long time ago... there is so much wrong with that theory, that it would take a week to write it down.

He sums it up in his statement...

"The physics may not be explained in a rigorous manner, but there is now far too much empirical evidence to doubt that there exists some process that has the periodic patterns that my original research has predicted. As a practicing engineer, I can accept this fact without having formal proof. If it works, use it..."

But the simplest proof that his longitudinal waves do not exist, is - if they did, they would show up on strain gauges placed on the barrels, and appear as many large bumps (as the waves reflected back and forth in the barrel), superimposed on a pressure trace.. which they do not.
 
Last edited:
ekp said:
Would you hunt with this rifle? Someone did free float the barrel and glass bed the recoil lug and tang area of the action.
Click to expand...


BTW, try the Barnes 130gr TTSX. It is my opinion that these new Barnes banded solids have changed the paradigm, I know a guy dropped, as in DROPPED, three elks this last yr using the Barnes 130's.

And they shoot

al
 
XBBR Shooter said:
I have read that a long time ago... there is so much wrong with that theory, that it would take a week to write it down.

He sums it up in his statement...

"The physics may not be explained in a rigorous manner, but there is now far too much empirical evidence to doubt that there exists some process that has the periodic patterns that my original research has predicted. As a practicing engineer, I can accept this fact without having formal proof. If it works, use it..."

But the simplest proof that his longitudinal waves do not exist, is - if they did, they would show up on strain gauges placed on the barrels, and appear as many large bumps (as the waves reflected back and forth in the barrel), superimposed on a pressure trace.. which they do not.
Click to expand...

So then in your experience ..what is the best way to develop loads given the limitation of 100yds. I always used to work up loads looking for the smallest group possible. I thought a more scientific approach would be good. Lacking the tools of a ballistician I thought the OCW method looked good.
 
ekp said:
So then in your experience ..what is the best way to develop loads given the limitation of 100yds. I always used to work up loads looking for the smallest group possible. I thought a more scientific approach would be good. Lacking the tools of a ballistician I thought the OCW method looked good.
Click to expand...

You are looking for an easy way - there are none. Experience in evaluating groups with different rifles helps spot patterns and problems, but it takes shooting.
 
XBBR Shooter said:
You are looking for an easy way - there are none. Experience in evaluating groups with different rifles helps spot patterns and problems, but it takes shooting.
Click to expand...

If you aware of my time and expense involved at the range you would not make some assumptions. I was looking for advise not a critique on my shooting. But thank you for you insight.
 
I have a suggestion, try a variety of loads with 4350 and a flat base bullet. Sometimes it can be as simple as not listening to what a rifle doesn't like. For hunting rifles I limit my group size to three shots. Also, I take care to rest the forend on the front bag so that the back of the bag is only about 2-3" from the front of the action. When working with a wood stocked rifle that was built to classic standards, I always evaluate the amount of barrel float, or contact location and pressure, both with an eye toward what stock movement may have changed.
 
Boyd Allen said:
I have a suggestion, try a variety of loads with 4350 and a flat base bullet. Sometimes it can be as simple as not listening to what a rifle doesn't like. For hunting rifles I limit my group size to three shots. Also, I take care to rest the forend on the front bag so that the back of the bag is only about 2-3" from the front of the action. When working with a wood stocked rifle that was built to classic standards, I always evaluate the amount of barrel float, or contact location and pressure, both with an eye toward what stock movement may have changed.
Click to expand...

That is precisely where I am going next. I am going to both Hornady, Nosler and Hogkin for suggested loadings taking the average of the maximum and starting loads and starting .6 below and work up by .3 to the middle and go .6 above.
 
Back when I could see worth a hoot I tried ladder load development, but it made my head hurt - BAD. Since then I've listened to people who I could see shot well, and/or who built rifles that shot well. Now when I work up a load I tend to tip the powder cannister up until I get the velocity I want, or change powders until I do. Then I fiddle and jiggle things around like seating depth until I get the accuracy that I'm looking for. It's pretty seat of the pants, but seems to work.

One thing that a local gunsmith who puts together some pretty accurate rifles told me when I was trying to get one rifle to shoot like I thought it should was that barrels with sharply angled leades tend to not like bullets seated up close to the rifling, while those with shallow leades tend to like bullets at or into the rifling. Many factory rifles, and I'm sure older custom rifles likely have fairly sharp leades so that seating the bullets well back from the rifling 0.030-0.060" can give better accuracy than crowding the rifling. I'd bet that this Sukalle rifle has a fairly sharp leade.

There's nothing quite like Ralph Gunriter and his 7 lb, half MOA (with all loads too) .300 Ultra Mag, who's got everyone convinced that if their hunting rifle can't shoot half MOA or better they shouldn't embarrass themselves by taking it into the woods. If a rifle can shoot 1 or 2 MOA, and the shooter can get the rifle to shoot that well from a field position he's good out to 300 yards on deer anyway. That's a pretty good distance, and a whole lot of people no matter how accurate the rifle would be hard pressed to hit a truck at 300 yards let alone a deer from a field position.

Now that I've insulted and offended a whole bunch of people I'll go away. :D
 
You must log in or register to reply here.
Back
Top