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Barrel Tuner Testing

02:05:38  | Bryan, Mitch, and Francis discuss the barrel tuner testing that they conducted at Applied Ballistics and is published in Modern Advancements in Long Range Shooting – Volume 3.  This is a long episode (2 hrs.+) as it goes deep into a topic that’s been somewhat controversial.  As such, it’s a great problem to myth bust with rigorous science and this conversation goes into the details of the testing and results of barrel tuner testing on 4 different rifles from 22 Rimfire to 308 Winchester.  Enjoy!

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9 Comments

  • Alfredo Rico says:

    Excellent coverage on the tuners. I had similar experiences where going back to the good setting didn’t produce the same results. I’ve also had some settings confirmed with three-shot groups.

    One of the interesting results reflects what you mention about mass on the muzzle. On my precision rifle with a Benchmark MTU profiled barrel, I was testing 5 muzzle brakes and included the EC Tuner/muzzle brake. I found a setting that resulted in a single hole, 3-shot group. I have never shot the rifle so well. My follow up group was almost as impressive. I was excited about the effectiveness of the tuner. I then removed the tuner and tested an MPA brake and shot another impressive single hole group. I scratched my head and suspected there was something about the weight and length of the brakes that made my rifle and ammo shoot so well.

    With my small sample tests on factory rifles with smaller diameter barrels and factory ammo, the tuner seems to make the groups smaller and more consistent. With your more extensive test, it makes me question whether I simply shot the gun better.

    The observation of the location of the screws is interesting.

    • Bryan Litz says:

      I think the presence of a weight/mass on the end of a barrel, especially a light contour barrel, can possibly improve precision. However, we’ve seen no evidence that small movements of that mass matter. Glad you found something that got you shooting small groups!
      -Bryan

  • Matt Barr says:

    Man this episode/chapter seems to be generating tons of buzz within the precision community. Might be a good topic for some follow-up discussion.

    • Bryan Litz says:

      Already planning on follow up testing! There are many claims, expectations, and ways that tuners are used. Our test was thorough, but narrow in scope. For example, our test wasn’t looking for positive compensation, which is something that would need to be tested at long range. To test for this, we’ll need to radar track all shots, and see if the measured BC and MV of each shot determine it’s vertical placement on target or if the tuner is able to produce some effect beyond the basic MV and BC of each shot.

      -Bryan

  • Ivan Bukvic says:

    I am not into barrel tuners, as I am not using them.
    To me, observation about additional mass is the most interesting one. As this is something I am testing too. Influence of a muzzle brake on a rifle precision.

    Equipment used: Rifle Sako TRG 22 .308 Win. 26″ barrel, Labradar (properly set and aligned), Handload (Lapua case, CCI BR2, Scenar-L 175gr, N140). Standard Sako TRG muzzle brake.
    Barrel cleaned (not to bare metal) and checked by borescope each start of 50 bullet batch to make comparation in a same conditions. Weather conditions was same, no significant wind.
    These are my findings

    Step 1 Load tuned with muzzle brake, not hot, bullet not close to riflings. 150 bullets loaded for test, 50 used for load tuning, total 200 bullets (all of same LOT, same case preparation, everything same). MV 775 m/s

    Muzzle brake installed. 50 bullets shot in 2 days training.
    – Avg precision: 0.4 moa. 5 shots grups 100m varying 0.3-0.5 moa, rarely 0.25 moa.
    One 10 shots group 300m 0.4 moa, mean radius 0.15 moa.
    – MV SD about 2 m/s (20+ bullets)

    Muzzle brake removed. 50 bullets in 2 days training.
    MV not changed. Zero shifted 0.6 mrad high, 0.25 mrad left.
    – Avg precision 0.5 moa. 5 shots groups 100m varying 0.4-0.6 moa, rarley 0.7 moa.
    One 10 shots group 300m 0.75 moa, mean radius 0.25 moa
    – MV SD about 3.5 m/s (20+ bullets)

    Muzzle Brake installed back. 50 bullets in 2 days training. Zero returned back to same value from first attempt, MV not changed.
    – 5 shots groups 100m same result as in a first attempt. One 10 shot group 300m 0.45 moa, 0.10 moa mean radius.
    – MV SD about 2 m/s (20+ shots)

    Step 2 should be with load tuned without muzzle brake. But that step is not done yet.
    In a future I am also planning to perform similar test with 2 attachments of a same weight but different length.

    Your test is much more detailed and significant then my. Influence of an additional mass on a rifle precision looks confirmed in your test. But what about MV SD. Did you maybe noticed on your test that MV SD was altered? In a with or without tuner comparation (not the tuner settings)?

    PS
    Note that I am using a bit faster powder with a bit heavier bullet. Case filled 90% as per Quick Load estimation. Neck tension 0.001″
    Better result on 300m compared to 100m is coming from a fact that I am getting more focused as distance is increasing.

    • Ivan Bukvic says:

      Just not to leave an open questions here.
      Testing completed.

      Difference in MV SD and precision arised from a fact not all powder burned in a barrel. Brake was dispersing jet of burning gases, thus assisting in more consistent bullet exit.
      Once powder charge got adjusted in order to burn powder completly inside the barrel, the difference completly wanished. Only zero shift remains.

      Both situation with and without muzzle brake have MV SD below 2 m/s with 15 bullets sample. No statistical difference.

      Precision on 300m
      With brake: CEP=0.18 (50 shots sample)
      Without brake: CEP=0.18 (100 shots sample)
      0% chance of being different.

      Conclusuon: Muzzle brake had no influence in precision in this particular case.

      • Bryan Litz says:

        Thank you for following up and reporting your results! It’s a great example of how we can come to the wrong conclusions when we don’t have all the data (or large enough sample sizes). Glad you figured out the load and can shoot great groups with or without the brake now!

        -Bryan

  • John Frost says:

    I looked into tuners recently and could not find any information that convinced me that there was an understanding of why they work or under what conditions. Your testing results don’t surprise me. After reviewing Jim Boatright’s simulation of a barrel, tuner and brake it appears that the location of position, velocity and acceleration crossings are dependent on barrel length and load. Unless the tuner is placed at the correct position on the barrel, of the correct weight, appropriate adjustment range, and for a specific load, the intended result will unlikely be found. Your thoughts?

    • Bryan Litz says:

      I agree. As many things revolve around the harmonic theory of precision, there is little-to-no supporting evidence or measurements of said harmonics. What is the amplitude and frequency of the harmonics? What’s the relationship between barrel contour and mass/movement needed to traverse 1 cycle or phase of harmonic?
      Everyone talks about finding nodes but the use of tuners and load development use sample sizes too small to actually resolve small differences in precision, weather caused by harmonics or other.

      It’s probably a good idea (for precision) to attach a weight at the muzzle, but rather than making it adjustable and telling ourselves an unverified story about harmonics, just let it sit there and do what mass does best: resist movement!

      My $0.02,
      -Bryan

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