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  1. #1
    Sharpshooter

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    Lowest sd and es not most accurate?

    Hey ingo,

    I just started load work ups with my new chronograph and rl23 for my 280ai.

    I shot 8, 3 shot groups with loads from lowest to highest working in small inciments...(.5 -.7 grain increments).

    The loads with the lowest es was not the most accurate...varying only 9 and 11 fps.

    The most accurate load actually had the highest es of 79fps....i noticed the same thing with h4831sc...to a much higher degree.

    Maybe it is my shooting or maybe my chronograph is faulty (caldwell).
    Some loads showed lower fps than the previous increment.

    I waited 8 to 10 minutes between most strings...go back inside, resize and load the next increment, ...barrel was never hot to the touch, but warm.

    Anyone else ever see this? Is there some science behind this?
    I would think that the most consistent fps would be the most accurate.

    Please and thank you
    Shred
    It's a trick..... get an axe.

  2. #2
    Sharpshooter 55fairlane's Avatar

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    Try this, the 6.5 guys method......load 10 rounds (1 round of each powder charge) in .2th grain increments till you get to max charge. Shoot thru your clock, the will be 2 "nodes" one on the low end one on the high end were your speeds are almost the same.....pick the higher "node" load 3 of each, and shoot for groups....May have to play with seating deapth, and you should see A) small groups , B) low ES &ED .....

    Hope this helps
    Quote Originally Posted by MarkC View Post
    To those of who lack such mad skills, your work, sir, is like magic!

  3. #3
    Premium Case Lube
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    ES and SD will help at distance. Close, you could be causing the issue, or perhaps they just donít group well at 100 yards. I run 13-14 SD, not all that great, that groups MOA at 1000 yards with wind, prob less without. 1/2 MOA at 200 yards, but stable shooting platform. For long distance, Iíd trust SD more than group size, IF you have a good chrono.

    Even the better chronos (magnetospeed v3, Labrador) are a bit off. A $75 Amazon chrono could be totally wrong, or worse, not repeatable.
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  4. #4
    Shooter

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    What are your factory ammo, or other loaded ammo averages?
    If the rifle is too new, and you don't have factory ammo averages as a base line, then you have an unknown firearm.
    Something as simple as barrel break in might be the issue.

    While 3 shot groups are OK for zero,
    I shoot 5 or 10 shot groups, or single target dots.
    The bigger the sample, the better the information.

  5. #5
    Grandmaster phylodog's Avatar

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    Quote Originally Posted by JeepHammer View Post

    While 3 shot groups are OK for zero,
    I shoot 5 or 10 shot groups, or single target dots.
    The bigger the sample, the better the information.
    This.

    3 shot groups are just this side of worthless. If you're truly interested in getting the most out of your efforts, 10 round averages are the only way to fly.
    There's lots of ________ on here who don't fit your particular stereotype, smearing us with goofball sophistry is what is out of line. It just makes gunowners look like *******s.

    - CarmelHP

  6. #6
    Shooter

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    I leaned in the Marines 10 rounds minimum, usually from a bagged rest or fixture was the only way to collect accurate data.
    We often fired 10 each 10 round groups (100 rounds total) to check for consistency.

    10 single shots at 10 different aim points (dots) makes you change your position 10 different times, no matter how small its 10 more chances for operator error to creep in.
    This is how shooters are trained to repeat shooting position, you miss the dot in a different spot, your fundamentals needed work since you weren't the repeatable part of the process.

    This isn't a real issue when shooting 'Minute Of Deer Heart' at point blank to 300 yards,
    But when you are shooting 800-1,200 yards, and the bullet is dropping out of the sky at high angle your fundamentals better be near perfect...

    I use a fixture a lot now, not being as strong as I used to be, long sessions at the bench wear me out, and a fixture doesn't get tired & shaky!

  7. #7
    Sharpshooter

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    I have "verified" the chrono with factory ammo in another rifle...280ai factory ammo isnt exactley easy to come by....the chrono was exactly what the hornady data said it should be.

    I also normally dont rely on 3 shot groups, however i am trying to conserve components and barrel life for load work up sake.
    My regular load is a 150 lapua scenar moving at 3000ish so i treat it like a magnum.

    I suppose i am looking for an easier, more reliable and cheaper way to do load development.

    Im still a bit fuzzy on what we are looking for with the 6.5 guys method....i dont have a book max or minimum to go by....
    I got up to 60.5g and no pressure signs at all, but erratic fps. Going to continue this work up until i get to pressure signs.

    When do i start adjusting oal? Once i have a "node" at the lower end and the higher end?

    Also the node is indicated by vertical and horizontal dispertion? Not group size?

    Quick load is starting to look very inexpensive.

    Please and thank you
    Shred
    It's a trick..... get an axe.

  8. #8
    Sharpshooter 55fairlane's Avatar

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    You look at the high end "node" then start adjusting your bullet seating deapth......your node is indicated by seeing shots (of different powder charges) having same to almost identical velocity (as shown by your crono)

    I sent you a pm

    Aaron
    Quote Originally Posted by MarkC View Post
    To those of who lack such mad skills, your work, sir, is like magic!

  9. #9
    Premium Case Lube
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    Google Scott Satterlee load development and watch the videos. In general, you develop a scatter plot in excel and find nodes (where increased powder doesnít necessarily mean increased velocity, a dip or plateau. This means, gun powder deviations make less difference. This is when your barrel, as a tuning fork, is resonating at a frequency at which the bullet exits a barrel at rest.

    To say, 10 rounds and you should be able to find your nodes (usually one high and one lo. Shoot three rounds at each .3 gr increment and average on the scatter plot for more consistency, but guys are finding total 10 rounds is sufficient. When you have your node, NOW you test within it.

    Same results as old school shooting for groups, but this is what caused the best groups with the old method.

    Shoulder bumping, seating bullet closer to lands, annealing (proper), neck tension, etc are all important, but the charge is the most important.
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  10. #10
    Sharpshooter

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    For this particular cartidge/rifle i anneal every 1 or 2 firings.
    I get higher es numbers with fl sizing than neck sizing so i only ever neck size... lee collet.

    Ran some more loads and got similar data. Going to start again with a new bullet/powder combo and do the work up in .3 grain intervals.

    Shred
    Last edited by Sirshredalot; 2 Weeks Ago at 21:16. Reason: Spelling
    It's a trick..... get an axe.

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