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Thread: Sweet Spot Speed and Pellet

  1. #1
    Rest in Peace Mike 05/12/2014

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    Default Sweet Spot Speed and Pellet

    Tests that we have conducted indicate that:

    Each rifle has an optimal speed range in relationship to the pellet used and this ideal range changes when the ingredients change (such as the pellet)

    That means that a rifle that is hot today using a 4.52 pellet batch 098 at 786 fps will need to be adjusted to 765 fps when 4.51 batch 093 are used and so on.

    What happens it appears is that at a certain speed turbulance is encountered causing destabilization of the pellet. At say 786 fps everything is fine and then a pellet leaves the barrel at 795 and this phenomena appears.

    It seems that the sweet spot is about 17fps deviation with the ideal setting for a particular combination adjusted to the middle of that range. This is not conclusive though.

    Furthermore it was found that 5 shot groups prove virtually nothing and the minimum grouping should be 40 shots.

    Using any other pellets than those sourced from JSB might be a waste of time ie. sub 800fps adjusted rifles---heavier pellets are a must for the higher speed rifles and the H& N brand also features in that range. There might be others.( Field Pellets)

    Barrel harmonics and other factors were not dialled into this experiment. Only the variance in pellet and velocity were taken into account.

    A one holer today might be a dog tomorrow! This continual striving for perfection makes shooting a very interesting past time sometimes frustrating too!.




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  2. #2
    Sharp Shooter

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    How big is the effect on group size at 50m when changing from 795fps to e.g. 765fps with a JSB(or variant) pellet.

    Is this totally dependant on the specific rifle?

    This will be almost impossible to determine if you do not have a 50m indoor range with a bench, a chrono and lots and lots of time.

    Isn't there some happy middle for most combinations or pellets at least?
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  3. #3
    Rest in Peace Mike 05/12/2014

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    Assuming you are jacking a hotshooter from 765 to 795 with the same pellet?

    The group will increase by a flyer appearing every now and again. The reason for testing 40 shots ---to eliminate the flyer --and the shape of the group is more important than size---round holes are preferable to odd shapes --main problem though are those flyers.

    Happy medium? Between 760 and 790.

    Some guns shoot better in wind than others---another science?

    Our tests were done indoors using a purpose made bench.

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  4. #4
    Sharp Shooter
    Doctor BAM

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    When all is said and done and calibrated, you will find that the medium in which you are shooting, the outside environment, has changed in temperature or humidity or something else, which will cause a marked difference in POI at longer distances......

    MMP, it is true that each rifle will have an optimal speed range to the pellet being used, but will only apply under the ambient conditions at the time of the test...... This is so far away from the conditions when we do FT or hunting, that accuracy obtained under semi-"controlled" conditions will not apply in real life......

    Just my 2c's worth.....

    malan
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  5. #5
    Rest in Peace Mike 05/12/2014

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    Quite true but as you correctly point out there are other factors, but the basics must be sound --a bad one does not improve because of the factors you mention, matters just get worse.

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  6. #6
    Inactive Member

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    Test setup, mark ranges on Side Wheel and elevation turret, aim ... shoot.

    HIT = 1 point
    MISS = 0 points

    Much easier and less complicated.
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  7. #7
    Rest in Peace Mike 05/12/2014

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    You are so right----it will take a lifetime to waddle through all the theory and then you die.
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  8. #8
    Protea FT Team '06/'07/'08/'09/'10/'11/'12/'13/'14
    National FT Champ '05/'08

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    AND STILL WONDER HWY YOU MISSED 1 SHOT ....LOL
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  9. #9
    Inactive Member

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    Walther!!!!!!!
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  10. #10
    Protea FT Team '06/'07/'08/'09/'10/'11/'12/'13/'14
    National FT Champ '05/'08

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    NO MUST BE HUMAN ERROR !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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  11. #11
    Inactive Member

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    Do you mean buying the damn thing in the first place? I agree!!!! hahahahaha
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  12. #12
    Inactive Member

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    Sorry, you two Hijackers stick to the thread!!!!!!!!!

    Gerty, remember he shot with a hot cookie!!!!!!!
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  13. #13
    Inactive Member

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    No excuse!!!! She and her hubby will probably not buy a pellet again this year. hahahaha
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