How do you find that screaming Accurate Load??

Discussion in 'Reloading' started by bigbuck, May 5, 2010.

  1. bigbuck

    bigbuck Well-Known Member

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    Okay I have a 300 RUM and I have a real nice load already at 87 grains of retumbo but I'm not running any faster than some powder packed 300 winmags ! I need more speed I've read in the past that Their is two nodes (whatever that means) one is an accurate load at the bottom (that's were I believe I'm at with this load) and then theirs supposedly one in the high side. I can't remeber if I read that kirby starts out in the red as far as the loading manuels call and then backs that load down 2 grains and finds a good load in that area. Correct me if i'm wrong but if you load this way I'm all ears . You are also welcome to share your load technique as well . Thanks for looking

    BigBuck
     
  2. RockZ

    RockZ Well-Known Member

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    I use a combination of blind luck and good fortune! It's been working so far .
    I've got numerous rifles that will put 3 shots in 1-2" at 565yds.

    Actually I use quickload and determine the best powders and target velocity that will get me to the desired node( which is the optimum barrel time-OBT).

    I do pressure workups at the range and shoot through a chrono so I can get actual data so that I can tweak the program to fit my exact parameters and results.

    Then I shoot groups to bracket the obt powder charge to find the optimum charge weight(ocw).

    I find the ocw and do a seating depth test to find the opimum seating depth.
    This should bring the shots into one nice hole.

    I then shoot a ladder at 565yds bracketing the charge again to see which powder charge shows the least vertical at longer range. Usually I change the powder charge about 1% until I find a load with very little vertical.

    I doesn't take many rounds or many groups to get a good load. Unless your rifle just doesn't like a bullet, but you will know that pretty quick.

    If you'd like you can send me your info and I can work something up.

    I need the cartridge, barrel length, bullet,oal,powder, water capacity, and if you are on the lands or off of them.
    If you have load and velocity data it would really help.
    Then I can see what might bring you to the higher node.
     

  3. bigbuck

    bigbuck Well-Known Member

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    Thanks PM sent.....

    BigBuck
     
  4. bigngreen

    bigngreen Well-Known Member

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    bigbuck, have you read the sticky on ladder testing. I have yet to try it my self but it seems like it may me a very good method.

    For now I find the max load then adjust it down a grain or two, then I shoot different COAL then I load a bunch of different primer and finally I adjust seating depth, it works but I burn a lot of components.
     
  5. bigbuck

    bigbuck Well-Known Member

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    Thanks bigngreen, i'll read the sticky . I usually find a load kindof like you do but i start from the lowest load data from my loading manuals and i let the paper tell me when to stop thing is I'm nopt running any faster than some 300 win mags . I'm going to see just how fast I can run the 210's and keep nice groups . I think i'll start a 200 yards and then move out to 500 then i'll try to get a tight group @ 500 . What would you call an extremely tight 3 shot group at 500 ?

    BigBuck
     
  6. Scout1

    Scout1 Well-Known Member

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    1/2 MOA or under @ 500 yards.

    Stick with RockZ, from reading his post his system is alot like mine. He'll get you where you want to be if you and your rifle are up to it.
     
  7. bigngreen

    bigngreen Well-Known Member

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    I don't stop working up till I hit max as comfirmed by chonograph and observed pressure signs then I look for the highest pressure with the best accuracy. I group shoot over a chronograph while working up a load, so far the highest pressure and accuracy node corespond with low SD and ES.
    Then I start shooting at distance and it seems to work OK and based on just a few years of trying to get extreem accuracy and speed for LRH.

    I like the longer range groups to reflect what the gun is capable of, if I shoot 1/2 MOA at 100 yrds I want to see it farther down range. Or MOC at 500yrds, Minute Of Coyote :D

    I would be tweeked if I was shooting a RUM at winmag velocity!!! :rolleyes:.
     
  8. bigbuck

    bigbuck Well-Known Member

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    HA now your talking Minute of Coyote :D

    It has been a while sence I've shot my rifle and looked at my load data . So i decided to go and see exactly what I was running as far as MV .

    AV MV of 2,845
    85.5 grains of retumbo
    3.675 OAL
    381 yard 3 shot group 3 inches center to center.

    This load produced .256 group at 200 yards.
    I think I messed up at the 381 yard target one round went just before I was completely ready.

    What I don't like about this load is it produced a 63.24 ES and a 33.64 SD and that sucks for way out their.

    One question for you guys I know I probably shouldn't have done it this way but I obatined my AV MV by a 3 shot average . Shouldn't I have done it by a 10 shot string wouldn't that be a more consitent way of obtaining an accurate AV ?

    BigBuck
     
  9. RockZ

    RockZ Well-Known Member

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    That is a great 200yd group! You may have your accuracy load.


    I would not use only 3shots to make any significant statistical deductions
    I quote three shot groups but shoot many of them to get a much larger test sample. Once numerous groups are successful I know I have a repeatable load.

    10 shots would be much better for velocity analysis. The more the better, within reason.

    I read an article written by a statistician and he said that the smallest meaningful test sample would be 7 shots.

    PM sent
     
    Last edited: May 10, 2010
  10. RockZ

    RockZ Well-Known Member

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    The sticky on ladder testing is awesome.
    I even color my bullets with sharpies. Makes it much easier to separate the good from the bad at long range!
     
    Last edited: May 10, 2010
  11. bigngreen

    bigngreen Well-Known Member

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    RockZ,

    What kind of target were you shooting at that showed up the sharpi color. I have a batch colored up sitting on the counter but I was wondering if there is a better target or backer.
     
  12. RockZ

    RockZ Well-Known Member

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    Just using a white target with a 3" orange dot in the center.
    if you can't make out the color, just get a q-tip and moisten it with alcohol (cleaning solvent if you don't have alcohol) , rub it on the bullet hole and the color will come out.