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Thread: barrel contour

  1. #1
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    barrel contour

    is there any difference in the accuracy of a light or heavy varmint contour verses a palmea contour they use in the camp perry type shoots given that you use the sme cartrige ,say the 6mm br improved or a 6mm ppc.
    gary b

  2. #2
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    I think it depends in large part upon barrel length. If all three contours are 20 inches long, there will not be much difference. At 30 inches, the difference will be much greater.

    I have a blueprinted Remington 700 action with a Krieger barrel chambered in .260 Remington. It is a Remington varmint contour. I asked for a 28 inch finished length. I got 30 inches. It has never shot like it should, regardless of which stock it wears or how it's bedded. I'm no looking to have it shortened to 27 inches.

  3. #3
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    Re: barrel contour

    FWIW
    I recently (2 seasons ago) started using tuners and had Krieger make me up a few modified Palma contours to use in LV. The results have been outstanding on both my own LV (2019 SOY & Calif State Championship)
    as well as the LV owned by the shooter who finished second. Obviously a small sample size, but 4 barrels in I’m a convert.
    With this contour you can throw a 6+ ounce tuner on it and still finish at 22” or more.
    I also believe but have no way of proving that the thinner profile because it has more “flex” is easier to tune, with a wider tune window.
    The tuner experts (Mike, Gene, Richard, etc.) might weigh in on this.
    JMO worth what I charge.
    Greg

  4. #4
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    Quote Originally Posted by wfcustom View Post
    FWIW
    I recently (2 seasons ago) started using tuners and had Krieger make me up a few modified Palma contours to use in LV. The results have been outstanding on both my own LV (2019 SOY & Calif State Championship)
    as well as the LV owned by the shooter who finished second. Obviously a small sample size, but 4 barrels in I’m a convert.
    With this contour you can throw a 6+ ounce tuner on it and still finish at 22” or more.
    I also believe but have no way of proving that the thinner profile because it has more “flex” is easier to tune, with a wider tune window.
    The tuner experts (Mike, Gene, Richard, etc.) might weigh in on this.
    JMO worth what I charge.
    Greg
    I agree Greg. I much prefer a barrel that shows me tune, or lack of it, over a barrel that is overly stiff by comparison. Fwiw.
    It's the same logic as using a tuner of say 6-7 ounces.
    Last edited by mwezell; 03-21-2020 at 09:00 AM.

  5. #5
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    100% agree.
    Todd

  6. #6
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    Maybe you could...

    tell me if I am off-topic, but here it goes:
    I am familiar with reverse taper barrels, used mainly with rimfire calibers (.22LR), the logic being that it slows down the whip displayed by all barrels when firing a round.
    The velocity of those rimfire cartridges is so much less than most center-fire calibers. Would this difference in velocity negate any good that a reverse barrel profile have if chambered in said center-fire caliber?

    Phil aka tazzman

  7. #7
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    Quote Originally Posted by tazzman View Post
    tell me if I am off-topic, but here it goes:
    I am familiar with reverse taper barrels, used mainly with rimfire calibers (.22LR), the logic being that it slows down the whip displayed by all barrels when firing a round.
    The velocity of those rimfire cartridges is so much less than most center-fire calibers. Would this difference in velocity negate any good that a reverse barrel profile have if chambered in said center-fire caliber?

    Phil aka tazzman
    I plan to try one when I can get a bbl, hopefully soon. Same theory applies, though and I expect it to work fine. The hard part is fitting within size specs for short range rules on barrel dimensions. It'll need to have a radius in front of the straight breech section, similar to a palma contour.
    I've done a similar thing by machining the barrel od down about 8 inches behind the muzzle, creating a hinge point, if you will. I don't recall the exact dimensions but it was a hv contour and I reduced the diameter by about .250 for roughly 2 inches, again, about 8 inches behind the muzzle. It shot very well but I want to try it with a true reverse taper.

  8. #8
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    great thread!

  9. #9
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    There is no doubt

    a palma contour with a 4 to 6 oz tuner has a wider tune window than a Lv-HV coutour. I have tested this a lot and it repeats every time. It all depends on what type of shooter you are. A runner or picker. If you are a runner this setup isn't for you! You will have vertical in the group because the bbl doesn't have enough time to settle down. If you shoot slower it works great. I am a runner when conditions permit and I just can't live with the vertical.

    Richard

  10. #10
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    Quote Originally Posted by Richard View Post
    a palma contour with a 4 to 6 oz tuner has a wider tune window than a Lv-HV coutour. I have tested this a lot and it repeats every time. It all depends on what type of shooter you are. A runner or picker. If you are a runner this setup isn't for you! You will have vertical in the group because the bbl doesn't have enough time to settle down. If you shoot slower it works great. I am a runner when conditions permit and I just can't live with the vertical.

    Richard
    In this part of the country, knowing when to run and when to pick is as important as doing either one well. I remember talking with you about this and I know I was very impressed with how fast you were shooting. Of course it was relative to group size or something. Do you mind sharing those details that I can't recall? I was impressed with your numbers.

    That said, it would be interesting to calculate or measure the difference in the vibrational frequency between say a lv and a hv barrel at different lengths and see how those changes correlate to running vs picking in real time. I also have to wonder how you are only getting vertical, if that's indeed the case. I have to wonder if it's the extra weigh that could cause only vertical, when tuners do change group size and shape on both vertical and horizontal planes. It seems unlikely that shooting too fast would only correlate to vertical when the bullet could be leaving the barrel at literally anywhere in its vibrational oscillation.
    Last edited by mwezell; 03-21-2020 at 10:56 PM.

  11. #11
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    Quote Originally Posted by mwezell View Post
    In this part of the country, knowing when to run and when to pick is as important as doing either one well. I remember talking with you about this and I know I was very impressed with how fast you were shooting. Of course it was relative to group size or something. Do you mind sharing those details that I can't recall? I was impressed with your numbers.

    That said, it would be interesting to calculate or measure the difference in the vibrational frequency between say a lv and a hv barrel at different lengths and see how those changes correlate to running vs picking in real time. I also have to wonder how you are only getting vertical, if that's indeed the case. I have to wonder if it's the extra weigh that could cause only vertical, when tuners do change group size and shape on both vertical and horizontal planes. It seems unlikely that shooting too fast would only correlate to vertical when the bullet could be leaving the barrel at literally anywhere in its vibrational oscillation.

    too bad a guy couldn't DAMP that somehow...... maybe with something heavy, and powdery.......hmmmmm......

  12. #12
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    I can give you a even better

    example of running fast making vertical. My rail which has a 1.350 bbl around 21" With a beggs style tuner with a weight of 6 oz you can run fast and shoot small. Shot a .15X agg with this setup last year at a nbrsa match, so I'm not talking about "backyard testing" down at the range. Anyway, this same bbl with a heavy tuner will shoot a .5 of pure vertical at 200 when running, slow down some and it will shoot a dot. Not all tuners have an influence on the H, but they can if the basic load is not tuned properly. And for AL, you can't damp out V from running with heavy powder, tried that.
    See the exact same thing with the bag guns also.

    Richard

  13. #13
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    Quote Originally Posted by Richard View Post
    example of running fast making vertical. My rail which has a 1.350 bbl around 21" With a beggs style tuner with a weight of 6 oz you can run fast and shoot small. Shot a .15X agg with this setup last year at a nbrsa match, so I'm not talking about "backyard testing" down at the range. Anyway, this same bbl with a heavy tuner will shoot a .5 of pure vertical at 200 when running, slow down some and it will shoot a dot. Not all tuners have an influence on the H, but they can if the basic load is not tuned properly. And for AL, you can't damp out V from running with heavy powder, tried that.
    See the exact same thing with the bag guns also.

    Richard
    There have been numerous national championships won and world records set with a tuner thats design is quite dissenting from your findings. One such record is Barts 600 yard .3xx group. I believe he's a runner and figured out how to tune out the vertical with this same tuner.

    Rather than arguing with you, I'll just say congrats on your .150 agg and let's just agree to disagree. The records speak for themselves. I'm not sure what the backyard range comment was about but I'm fortunate enough to have a good place to test in my backyard. It's been a big help and it was a factor in my championship win last year. So yes, I compete at registered matches, too. Shooting at both, I have been able to determine that tuners work exactly the same at a match as they do on my backyard range. In fact, I've been able to confirm this with some fancy equipment, like accelerometers and oscilloscopes. Those tools and a nice backyard range allow me to cut through a lot of internet chaffe.

  14. #14
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    Your missing the point

    Quote Originally Posted by mwezell View Post
    There have been numerous national championships won and world records set with a tuner thats design is quite dissenting from your findings. One such record is Barts 600 yard .3xx group. I believe he's a runner and figured out how to tune out the vertical with this same tuner.

    Rather than arguing with you, I'll just say congrats on your .150 agg and let's just agree to disagree. The records speak for themselves. I'm not sure what the backyard range comment was about but I'm fortunate enough to have a good place to test in my backyard. It's been a big help and it was a factor in my championship win last year. So yes, I compete at registered matches, too. Shooting at both, I have been able to determine that tuners work exactly the same at a match as they do on my backyard range. In fact, I've been able to confirm this with some fancy equipment, like accelerometers and oscilloscopes. Those tools and a nice backyard range allow me to cut through a lot of internet chaffe.
    first, I meant nothing bad by the backyard range comment. I have Charlene's Meadow just 100 yds away from the shop and test there about every day. If it won't shoot there I am sure not taking it to a match. I know about testing equipment and also realize what goes into getting valid data. Your right however that we don't agree on some of the results, but that's ok, we both agree that tuners work. There is just more than one way to get the results we want. The best test of all is the target. I tell the guys when teaching tuning classes that the rifle is speaking to you on the target, learn what it's telling you.
    Stay well during trying time and wish you the best of luck.

    Richard

  15. #15
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    Quote Originally Posted by Richard View Post
    first, I meant nothing bad by the backyard range comment. I have Charlene's Meadow just 100 yds away from the shop and test there about every day. If it won't shoot there I am sure not taking it to a match. I know about testing equipment and also realize what goes into getting valid data. Your right however that we don't agree on some of the results, but that's ok, we both agree that tuners work. There is just more than one way to get the results we want. The best test of all is the target. I tell the guys when teaching tuning classes that the rifle is speaking to you on the target, learn what it's telling you.
    Stay well during trying time and wish you the best of luck.

    Richard
    Yes, trying times indeed. May we all stay well and this virus die out very soon and a vaccine be made that can render it harmless.
    Good shooting!--Mike

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