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Thread: barrel contour

  1. #16
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    Back on subject..I've been shooting my own contour barrel and won last years UBR Nats with it. Several are reporting the same I've been seeing from it. ABC has the contour program on file and is called the "Ezell Tuner BR" contour. It's really not far from a standard LV but I want to test the reverse taper and then work with something closer to a HV that is more tuner sensitive as well. There's a ton of confusion about barrel stiffness/contours. Case in point...most people believe that a 1.250 is super stiff. Per inch, it is but length affects barrel stiffness faster than diameter. For example, a 28" 1.25 straight is actually less stiff than a 24" hv or a 21" Lv. I need to double check my numbers to be precise but those numbers stand out as common examples that I have compared. Lilja has a great calculator for barrel stiffnes..very interesting to play with. The stiffness calculator is part of his barrel weight calculator program.

    Here's a link
    https://riflebarrels.com/computer-software/

    Nevertheless, it's quite interesting to plug different numbers into it and see what it spits out. When I first started testing tuners, I made a fixture to hold a barrel and measured muzzle deflection induced by a weight attached near the muzzle, with a test indicator. This program does that for you.

    Several people have known for years that their lv will shoot right with their hv and others have played with Palma contours as well. Bottom line is, there seems to be a concensus among those people that to a large degree, smaller barrels can and do shoot right with heavier ones. My approach is more along the lines of finding a combination that makes weight and tunes easier and with a wider tune window, much along the same lines as a tuner does.

    Barrel whip gets discussed from time to time with a negative connotation. To a point, barrel whip is a good thing, not a bad thing. I can't tune out what I can't see on target so by adding weight at the muzzle or using a less stiff contour barrel, there is more muzzle deflection(or whip)..and it shows up on target with repeatabilty. The increased muzzle deflection simply makes tune, or lack of it, more apparent on target. That alone makes knowing how and when to make a tuner(or load) adjustment more recognizable. That's the bottom line. But there is the added benefit of a wider tune window due to a less stiff barrel, or one with a tuner, vibrating at a lower frequency. That's just a fancy way of saying that it's vibrating slower..with wider nodes and space between nodes. So, it shows tune more apparently on the target and doesn't fall in or out of tune as rapidly as a stiffer barrel. In simple terms, that's what a tuner does, plus gives the ability to change tune without changing the load. More later, if there is interest here.
    Last edited by mwezell; 03-22-2020 at 09:03 PM.

  2. #17
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    Quote Originally Posted by mwezell View Post
    Back on subject..I've been shooting my own contour barrel and won last years UBR Nats with it. Several are reporting the same I've been seeing from it. ABC has the contour program on file and is called the "Ezell Tuner BR" contour. It's really not far from a standard LV but I want to test the reverse taper and then work with something closer to a HV that is more tuner sensitive as well. There's a ton of confusion about barrel stiffness/contours. Case in point...most people believe that a 1.250 is super stiff. Per inch, it is but length affects barrel stiffness faster than diameter. For example, a 28" 1.25 straight is actually less stiff than a 24" hv or a 21" Lv. I need to double check my numbers to be precise but those numbers stand out as common examples that I have compared. Lilja has a great calculator for barrel stiffnes..very interesting to play with. The stiffness calculator is part of his barrel weight calculator program.

    Here's a link
    https://riflebarrels.com/computer-software/

    Nevertheless, it's quite interesting to plug different numbers into it and see what it spits out. When I first started testing tuners, I made a fixture to hold a barrel and measured muzzle deflection induced by a weight attached near the muzzle, with a test indicator. This program does that for you.

    Several people have known for years that their lv will shoot right with their hv and others have played with Palma contours as well. Bottom line is, there seems to be a concensus among those people that to a large degree, smaller barrels can and do shoot right with heavier ones. My approach is more along the lines of finding a combination that makes weight and tunes easier and with a wider tune window, much along the same lines as a tuner does.

    Barrel whip gets discussed from time to time with a negative connotation. To a point, barrel whip is a good thing, not a bad thing. I can't tune out what I can't see on target so by adding weight at the muzzle or using a less stiff contour barrel, there is more muzzle deflection(or whip)..and it shows up on target with repeatabilty. The increased muzzle deflection simply makes tune, or lack of it, more apparent on target. That alone makes knowing how and when to make a tuner(or load) adjustment more recognizable. That's the bottom line. But there is the added benefit of a wider tune window due to a less stiff barrel, or one with a tuner, vibrating at a lower frequency. That's just a fancy way of saying that it's vibrating slower..with wider nodes and space between nodes. So, it shows tune more apparently on the target and doesn't fall in or out of tune as rapidly as a stiffer barrel. In simple terms, that's what a tuner does, plus gives the ability to change tune without changing the load. More later, if there is interest here.
    I think you've nailed it Mike,

    and I'll read anything you choose to post.

  3. #18
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    While barrel stiffness is a factor in node width and tunability, it's remarkable how predictable it is with my tuner. So much so, that I look for and expect there to be four marks between completely in tune to completely out of tune...on a typical short range rifle and barrel. I can even predict group size and shape at each mark within that range. I say that because there are several lengths and contours that fit with and are commonly used in short range...Like 19-1/2"23" LV barrels to 22-26" hv contours. Between those contours, I expect to see basically the same tuner mark values. When we step up to more popular long range lengths and contours, such as 28-30" HV and 1.250 straights, tuner value changes, but just a little bit., to typically five marks from in tune to completely out of tune. So, while stiffness does matter enough to quantify in this regard and on target, it's still a relatively small amount. But if you run the numbers through the stiffness calculator, it makes sense that there really isn't a huge difference there either. Keep in mind that with my current tuner, one mark is equal to .001" of tuner travel.

    Now, lets say we start with a load that is giving us 3,000fps at 50 and as temp rises to say, 75, it now gives us 3,020fps. Reasonable numbers IME, but I use them just as much for easy math...
    So, that 20fps increase is equal to .6% velocity increase.
    Lets also say that the bullet is in the barrel for nominally 1.5 milliseconds at 3000fps. That's a pretty tiny amount of time, I think we will agree. But, at 3,020fps, it's in the borefor less time...for .6% of 1.5 milliseconds less time! Now were talking REALLY tiny! So the bullet is reaching the muzzle sooner in time, right? How do we bring it back to perfect tune? We speed the vibrational frequency up by, guess what... .6%!! So it's calculable and tuners aren't voodoo, afterall!

    That's relevant because a stiffer barrel vibrates at a higher freqency...or faster, with less space and time between nodes. A less stiff barrel, slower, with wider nodes that are spaces further apart. This makes staying in tune easier and less dramatic, to a degree. I mean, the less stiff barrel deflects more...or has more INITIAL amplitude.
    I want to stop and clarify this statement before moving on. Physics teaches us that when we add weight to the muzzle that amplitude is decreased. This is true..OVER TIME! So yes, amplitude does decay faster over a period, netting a reduced amplitude during a wider time frame...But we're dealing with nominally 1.5 milliseconds and the amplitude is increased by barrel droop, even before we pull the trigger! Hopefully, we're together on this, because it can rightfully be a point of contention. Just remember that we are dealing with vibration for a VERY short period of time.
    Back to my point about more muzzle deflection being a good thing...Since I can't tune for what I can't see on target, a muzzle that deflects more, make my "out of tune" groups bigger than they would be without a weight at the muzzle. That sounds bad but it's not, because I can't tune for what I can't see on the target, especially in real world match conditions. This is true whether you use a tuner or a barrel that is less stiff..same, same, in most regards, except the tuner is adjustable, at the bench.

    I've been wanting to talk about this and want to while it's fresh on my mind and I'll stop for now....and I don't mean to make this thread all about tuners. It's just that barrel stiffness is a key in how they do what they do.

    Anyway...There are two camps about how to tune when planning to use a tuner. One says to tune the load to the rifle before putting the tuner on. The other is to do load work up as normal, with the tuner on but don't touch it...forget it's there.

    BOTH WAYS WORK!

    Oh but how? Easy..The best way to look at things is, as the barrel moving in a simple, one dimensional sine wave pattern, where the nodes just appear the same...over and over again, repeating. Yes, there's more going on but the tuner being at the end of the barrel is adjusting the average of everything happening behind it.
    Now, REPEATING is the key word because that's what takes place and it's how doing load work up works either way..on or off. Because the barrel crosses a sweet spot over and over again. Again, only .004-.005" tuner travel from dotting up to worse than you ever thought it could shoot....then it starts over, and over, and over..fore all intents and purposes her, forever.
    It crosses these sweet spots that we call nodes with a tuner or without. My tuner lowers the frequency by nominally 30% over no tuner, yet it works both ways? Yes! The barrel crosses these sweet spots without any weight, or even a net loss of weight...as it does with the tuner but the nodes are about 30% further apart due to the lower frequency created by simply having a weight at the end of the barrel. Long story short, if you do load work up without the tuner on, you're loading to a node that shoots but is about 30% from the one where it will shoot the same way within about four marks at most, with the tuner. Is that clear? The sine wave example is the way to think about it...Bullet exit happens, ideally, just prior to the vertical apex of the barrel swing...with the tuner or without it. The fact that it works both ways just proves that tune repeats over and over, forever...from a net loss of weight at the muzzle(threaded for a tuner) to a net gain of several(many) ounces, with one. Bottom line here is two things...First, you can do it either way with equal results IME. Second is that it just repeats, over and over. That's important to remember. Other than positive compensation, there is no reason why one vibrational node would be better than the next...from the standpoint of which will shoot smallest...No difference. I've shot some tiny groups at the bottom of the barrel swing.

    More later...

  4. #19
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    I almost can't

    believe what I'm hearing. I have been preaching and teaching this for the last four years! I had made a post several years ago about being able to turn the tuner and knowing what the result would be.
    You totally blew it off like I didn't know what I was talking about. And now your Moses come down the mountain?? Well, glad your coming up to speed on how to run a tuner.

    Richard

  5. #20
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    Quote Originally Posted by Richard View Post
    believe what I'm hearing. I have been preaching and teaching this for the last four years! I had made a post several years ago about being able to turn the tuner and knowing what the result would be.
    You totally blew it off like I didn't know what I was talking about. And now your Moses come down the mountain?? Well, glad your coming up to speed on how to run a tuner.

    Richard
    Are you talking to me?

    I have no idea what you're talking about. The one thing I've tried to be is consistent. I'll assume you have me confused with someone else and let this go, or that there was some misunderstanding. Either way, it explains a lot.
    If you had been paying attention, you'd know that I've maintained the same basic message about tuners for a long time, particularly since vibration testing, as there was a lot learned at that time.

    Do you have anything you'd like to add on the subject? Feel free but your last couple of posts were disappointing.

  6. #21
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    I am talking to

    you Mike,

    When I posted about how you can know with certainty what to do with a tuner you had came back some snide comments about how hard I was making this. And now you come back with the results I was getting years ago. The results you are getting are good, it's not that. When you start out with MY tuner why not just place a full page add. I gotten the same results with your tuner and a host of other ones. I understand you sell tuners, I do not have any vested interest in anybodys tuner. I do this for the interest of the sport and people. So be whatever, it's just that way, I can read in-between the lines from your first post. Just let it go.

    Richard

  7. #22
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    Quote Originally Posted by Richard View Post
    you Mike,

    When I posted about how you can know with certainty what to do with a tuner you had came back some snide comments about how hard I was making this. And now you come back with the results I was getting years ago. The results you are getting are good, it's not that. When you start out with MY tuner why not just place a full page add. I gotten the same results with your tuner and a host of other ones. I understand you sell tuners, I do not have any vested interest in anybodys tuner. I do this for the interest of the sport and people. So be whatever, it's just that way, I can read in-between the lines from your first post. Just let it go.

    Richard
    Apparently, you wont even agree to agree, then. Lol! It's also apparent that you haven't been paying attention for years. Why are you now?
    You could just not bother reading or replying.
    Your posts are focussed on attacking me rather than bringing anything of value to the discussion. Please be constructive and positive. Thanks in advance.
    Last edited by mwezell; 03-25-2020 at 09:14 AM.

  8. #23
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    whatever mike

    spin it how you want.

  9. #24
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    Quote Originally Posted by Richard View Post
    spin it how you want.
    Spin what Richard? What are you upset about?

  10. #25
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    Mike,

    I'll get back to you. Have to leave for awhile. Sorry for being such a grump, I also have invested a tremendous amount of time with tuners and I know you have to. I think were on the same page with a lot of this tuner stuff. I'll just leave it at that for now.

    Richard

  11. #26
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    Quote Originally Posted by Richard View Post
    I'll get back to you. Have to leave for awhile. Sorry for being such a grump, I also have invested a tremendous amount of time with tuners and I know you have to. I think were on the same page with a lot of this tuner stuff. I'll just leave it at that for now.

    Richard
    No need. The bickering is getting old. But please do offer something good to this thread. I know you've got a lot of good experience that you could share here.

  12. #27
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    Hope the original OP

    got his questions answered. On to tuners,

    This is what I have seen over the years, your results may differ somewhat but would guess by not much.
    The tuners tested all showed the same basic tuning window in for-aft movement. .005-.006 half node or .010-.012 full node. Was there a better node to be in? Not really that I could find and I think you could wear a bbl out searching.
    A important part of learning the tuner is understanding where you are in the node. You cannot predict how to turn the tuner unless you understand that concept. Think about tuning with powder. Some say you need to go up on powder when you have Vertical, others say that you need to decrease powder to get rid of vertical. In reality both are correct both tuning from opposite nodes. It's the same for tuners. I tune where the group gets tighter as you turn the tuner toward the breech, if the group gets larger I know that it's just opposite of where it want to be. The other way is fine also. The point being you need to know where your at to make good tuning decisions. As far as running the tuner goes it really is that simple.
    Once you have mastered that part, where you can actually turn the tuner with no guess work your well on the way to learning the next very important thing which is tuning for the condition out on the range.
    One other thing that needs to be mentioned because I see it so many when giving lessons here at Charlene's Meadow.
    Just because the tune is right today, does not mean that it will be tomorrow. What can be hard for some to grasp is the gun might be on the opposite node the next day and the tuner is not doing what they expect. It's not hard to fix once you realize what is happening. But can be very frustrating for a new tuner user. If there is no practice before a match starts I always take the time on the sighter to be sure the tuner is one the node I want. That way you will make sound decisions during the match.
    Practice practice practice. When giving lessons I will sometimes give the tuner a big twist and then start the clock. It gives shooters a feel for the timeline pressure that you can sometimes be under when things aren't working.
    Again, this is just the experience I have had over the years and hope this helps tuner users.
    There are other things that will come into play as you gain more experience but that is out of the scope of basic tuner use.

    Richard

  13. #28
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    For what it is worth, I have had a tad of experience with tuners. More than 10 years ago, we tried one on a friends Young Rail Gun. I even made a write up on our experience on this Site.

    It had a 1.450 barrel. I made a 20 ounce snubber tuner for it, just a scaled up version of my tuner we use on bag guns.

    It deadened the barrel quite well.

    At the range, we got his Rail shooting quite well. He then decided to run a group as fast as he could cycle the Action and put it against the stop.

    The groups were abysmal. .300+ wads. He slowed down, the thing shot dots.

    By theory was the barrel simply was not settling after hitting the stop. You could feel the vibration as it hit the stop.

    I figure it took at least one second after hitting the stop to allow it to settle.

    We then removed the tuner, and ran a group as fast as he could. The Rail did not shoot quite as well sans the tuner as with when shooting slow, but it shot just as good running the group.

    I have not had a tuner on a Rail since. I might try agin in the future, though.

    I am open for suggestions
    Last edited by jackie schmidt; 03-26-2020 at 12:31 PM.

  14. #29
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    I have a really

    good bbl on my rail at the moment and will shoot small either running or picking. I made beggs style tuner that weighs 8 oz and it tunes just like the bag guns do. A fellow sent me a tuner to try that weighed 16oz. It would tune very well and shot great shooting slow. Running groups were not that great, just like you I don't think the bbl had enough time to settle down with that much weight hanging on the front. Why don't you try a tuner in the 8-10oz range and see what you get. I am running a 1.350 bbl for your info so that might change things some but don't know that for a fact.

    Richard
    Last edited by Richard; 03-26-2020 at 12:55 PM. Reason: spelling

  15. #30
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    Quote Originally Posted by Richard View Post
    got his questions answered. On to tuners,

    This is what I have seen over the years, your results may differ somewhat but would guess by not much.
    The tuners tested all showed the same basic tuning window in for-aft movement. .005-.006 half node or .010-.012 full node. Was there a better node to be in? Not really that I could find and I think you could wear a bbl out searching.
    A important part of learning the tuner is understanding where you are in the node. You cannot predict how to turn the tuner unless you understand that concept. Think about tuning with powder. Some say you need to go up on powder when you have Vertical, others say that you need to decrease powder to get rid of vertical. In reality both are correct both tuning from opposite nodes. It's the same for tuners. I tune where the group gets tighter as you turn the tuner toward the breech, if the group gets larger I know that it's just opposite of where it want to be. The other way is fine also. The point being you need to know where your at to make good tuning decisions. As far as running the tuner goes it really is that simple.
    Once you have mastered that part, where you can actually turn the tuner with no guess work your well on the way to learning the next very important thing which is tuning for the condition out on the range.
    One other thing that needs to be mentioned because I see it so many when giving lessons here at Charlene's Meadow.
    Just because the tune is right today, does not mean that it will be tomorrow. What can be hard for some to grasp is the gun might be on the opposite node the next day and the tuner is not doing what they expect. It's not hard to fix once you realize what is happening. But can be very frustrating for a new tuner user. If there is no practice before a match starts I always take the time on the sighter to be sure the tuner is one the node I want. That way you will make sound decisions during the match.
    Practice practice practice. When giving lessons I will sometimes give the tuner a big twist and then start the clock. It gives shooters a feel for the timeline pressure that you can sometimes be under when things aren't working.
    Again, this is just the experience I have had over the years and hope this helps tuner users.
    There are other things that will come into play as you gain more experience but that is out of the scope of basic tuner use.

    Richard
    Richard, excellent post. Thank you and we apparently agree way more than not. That's a good thing, I believe, At least we're pulling in the same direction.

    As for groups opening up running vs picking, I will only add a couple of things to consider rather than saying one is right and one is wrong.
    I shot some rf for a while where it's common to see 24"x .850-.900 straight barrels with 8-11 ounces tuners being pretty common. When you close the bolt, you can literally watch the barrel bounce!
    Second is in regard to when vibration starts. I believe it starts even before the firing pin hits the primer and then..we have a 65,000 psi pressure vessel under great tension, that does indeed induce a whipping action from the barrel. The speed of sound/vibration through stainless is roughly 20,000 fps, so even the vibration of the firing pin hitting the primer will travel back and forth several times before the bullet even leaves the case..then we have that 65,000psi pressure wave traveling down the bore.

    Just things to ponder that may or may not be relevant, but I believe they are worth consideration.
    Last edited by mwezell; 03-27-2020 at 11:21 AM.

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