Interesting Tuner Results

Discussion in 'Main Message Board' started by Kyle Schultz, Mar 12, 2019.

  1. Kyle Schultz

    Kyle Schultz Gold $$ Contributor

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    I'm new to SR group shooting. I recently had my 6 PPC barrel (146 rds) threaded for Mike Ezell's PDT tuner. I previously had tuned the bare barrel at 29.2 gr N133 using Bart's Bullets 68gr Avenger bullet seated 0.012" into the lands from a touch.

    Yesterday I installed the tuner. It "bottomed out" at a setting of 18. I then backed it out 1/2 turn until the "0" mark on the tuner lined up with the witness mark on the barrel. I then shot 3-shot groups at each setting. If the 2-shot group was not good, I did not shot the 3rd shot. The 2-shot groups are marked with an asterisk. Target below.

    Tuner Results.PNG

    Some interesting results. The "book" says that the nodes repeat themselves about every 8 tuner marks. And I pretty much saw that behavior. I had good nodes at 0/1, again at 8/9/10, and again at 19/20/21. I mistakenly shot setting 27 twice and while the first group was good, the second was not so who knows.

    At the end of the day, I reshot groups at tuner settings 19, 10 and 1. Target not attached. The groups for 19 and 10 were not good but the 5-shot group at 1 was good. I roughly measured the group size at 0.157".

    It does appear to me that the groups print systematically. POA was 12 o'clock on the moth ball. You clearly can see the POI of the groups fall from 0 to 8 and then start climbing. From a peak at 14 the groups trend lower until they bottom out around setting 21. Then they start climbing again.

    One mistake I may have made was shooting this test with once-fired brass. The final 5-shot group at 1 that shot the 0.157 group was shot with twice-fired brass. Their average velocity was 23 fps faster than the average for the once-fired brass.

    My plans are now to retest 2 regions (dare I say... quadrants) of the tuner. That being the settings around 0/1 and the settings around 19/20/21.

    Your comments and advice are welcomed and appreciated.
     
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  2. ALBULLET

    ALBULLET Silver $$ Contributor

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    8-12.... 16-21.... Look good..,!!!! But I would like to see the same test again. I have also been working with the Barts Avenger 68 ... 29.2. /29.9 N133.
    My barrel also liked .012/.013 into the lands which is .007 off a HARD JAM.
    Thanks for the report. Please let us know how the next test goes.

    Thanks Scotty Grimes
     
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  3. jackson1

    jackson1 Silver $$ Contributor

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    Thanks Kyle for the report. Been thinking about one for my 6BRA.
     
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  4. Texas10

    Texas10 Gold $$ Contributor

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    I'll be following this with great interest. A shooting buddy and I both just bought a Harrells tuner/brake. His is on a 6.5CM and it shot great at 0 setting. I've yet to shoot mine on a new 6BR Shilen, so this will be quite interesting.
     
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  5. MislMan

    MislMan Silver $$ Contributor

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    Awesome data! Thanks for posting this.
     
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  6. CharlieNC

    CharlieNC Gold $$ Contributor

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    If I understand correctly, most of the good settings did not reproduce upon retesting? If it was me shooting and looking at group sizes of .1-.2 as being significantly different, I would suspect it was my ability (or lack of) that caused this and I would re-shoot the entire exercise until the results presented a consistent story.
     
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  7. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    There does seem to be what I call "noise" to the test. Not far off but not exactly what I typically see either. I've msgd Kyle about it and I'm confident he'll get it dialed in nicely.
     
  8. Kyle Schultz

    Kyle Schultz Gold $$ Contributor

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    I too would have liked to see more consistency. Here is the retest I mentioned but didn't include in the original post.

    Tuner Retest.PNG

    Settings 19 and 10 did not retest. Setting 1 did retest successfully. But as noted earlier, it was shot using 2X brass. The POI is different and the velocity for the 2X brass was 23 fps faster than for the 1X brass.

    I certainly agree more testing is needed. But I'm hoping I've at least roughly defined the areas of the tuner that are the most promising. We shall see.
     
  9. rimfiremac

    rimfiremac

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    Hate to say it, but I bet that if you picked a tuner setting and shot another test target like the initial one, the results would look identical to that with various settings as a function of the normal statistical distribution of the combustion cycle. 99% of the benefit a tuner yields occurs when you bolt it to the barrel. Moving the tuning ring back and forth, from a dynamics perspective, does zero.

    I may be wrong, but I'm willing to bet on my perspective if you're interested in shooting another 15 rounds to test it.
     
  10. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    I completely and 100% wholeheartedly disagree. I've done these tests hundreds if not thousands of times, along with vibration analysis testing to actually measure and quantify the differences...and it's always repeatable. But we can just agree to disagree.
     
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  11. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    Kyle, I'd retest 27 also. The results on either side of it are most typical of what I see.
     
  12. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    Kyle, I had forgotten to hit the send button on the email I thought I sent earlier. You should have it now, I think. Lol!
     
  13. rimfiremac

    rimfiremac

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    Not point to debate on the screen, just shoot a line of five three shot groups on one setting with this same load and prove me wrong, because I hope I am, but I think I'm not ;)
     
  14. Engrbill

    Engrbill

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    Kyle,
    I have also been testing with Mike's tuners on two different barrels. I am using 29.2 of N133 and my own 7/10 ogive 66G BT's seated same as yours with Norma brass in a tunnel. I have the same results as to the groups repeating every 5-6 numbers. I have not had good success with getting sweet spot numbers to repeat good groups consistently. I'm interested in your future testing.
     
  15. CharlieNC

    CharlieNC Gold $$ Contributor

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    Absolutely, in ANY experiment having a feel for the noise is essential to achieving a reliable outcome which requires a suitable signal:noise ratio. If the best I can hold due to rests, technique, etc results in .5 moa groups then I am grasping at straws to distinguish a .3 from a .2 moa because those could easily be part of the noise. More samples will help. Or increase the signal e.g. instead of 10 shots that are .3gr apart to check velocity difference, load 2 each at 5 charges covering a 2gr range to overshadow the noise. Personally I am confident in the results when shooting a single shot ladder for charge weight based on poi, but when looking at groups for seating depth I will always retest.
     
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  16. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    I'd be happy to discuss it with you any time.
     
  17. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    I've done it more times than I can count and you're looking at a test target on this thread, doing it too. And I just told you that I've tested it extensively including vibration measurement equipment that allowed me to quantify the changes with and without regard for what the target says...but the two do in fact coincide with one another.

    Your logic is the same that Calfee preaches and is proven wrong by science and physics. I don't feel the need to prove that but you would probably benefit from moving away from a "theory" based on a truck antenna that is disproven, and on to something that is supported by science. We don't have the same ammo inconsistencies with cf that you deal with in rf either.
     
  18. gunsandgunsmithing

    gunsandgunsmithing The best tuners and wind flags on the market Gold $$ Contributor

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    Just conversed with Kyle. He was shooting a 8-10mph switching 10o'clock-1 o'clock headwind when this was shot. I don't know about anybody else, but that condition eats me up. I'm guessing some of the "noise is from that. Not a bad target, considering. I just wouldn't trust myself enough in that condition to do initial tuner testing.
    I encourage initial tuner testing be done in the very best conditions possible and with flags. Kyle did have his flags out. It woulda been worse if I'd shot it. Lol!

    Once you're intimately familiar with the tuner's effect on group size and shape, you can make adjustments on the fly in conditions. The key is looking for the expected result for a given tuner setting. IOW, once you establish what in tune looks like, 1 mark, 2 marks, etc look like...and it does it on paper, that's when you move the tuner accordingly. If the conditions are too tough to see a predictable result, leave it alone.

    I'll edit to say that I think this is the most important key to tuner success.
     
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  19. Marksman63

    Marksman63

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    Are you going to test your tuning for different temperatures?
     
  20. Kyle Schultz

    Kyle Schultz Gold $$ Contributor

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    Yes.

    Latest update is that I'll be retesting the tuner next week in Gene Beggs' test tunnel in Odessa. That should eliminate the wind influence from the results.
     
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