Help with load analysis (6BR, 80GR Berger FB, N135)

Discussion in '6BR, 6BR Improved & Wildcats' started by Poor Shot 65, Sep 11, 2019.

  1. Poor Shot 65

    Poor Shot 65 Silver $$ Contributor

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    Hi

    I just rebarreled my 6mmBR and I am looking for help in determining the load to use.

    Barrel is a Krieger LV 8 twist chambered with a .60 free bore.

    Shooting 80GR Berger FB bullets. Bullets have been seated .015 jammed.

    Powder is N135

    Targets are at 100 yards. Each square of the target (I believe) is 1ā€.

    At the start of this session, the barrel had 20 rounds shot through it.

    Please see all the attachments for target info and raw numbers (speed, SD, ES etc). As my handle says, I am not a great shot, but im looking for a little direction here (stick with N135 ? which charges look good ? direction to go with seating etc ? or just give up :> ?) .

    Looks to me that there are two possible nodes:

    29 to 29.3 or 31 to 31.4 .. nothing looked really good though.

    at 32 I saw signs of pressure - so im not comfortable going above 31.7 at this point in time.

    Thanks

    Adam
     

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    Last edited: Sep 11, 2019
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  2. urbanrifleman

    urbanrifleman Site $$ Sponsor

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    Do a seating depth test. I think they shoot best jumped.
     
  3. urbanrifleman

    urbanrifleman Site $$ Sponsor

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    Take 29.3 and do a test at
    20 in
    10 in
    5 in
    5 out
    10 out
    20 out
    30 out

    Do it twice or even three times. One will shoot the best.
     
  4. Poor Shot 65

    Poor Shot 65 Silver $$ Contributor

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    Sure thing. I will try to get that done this Friday. Thank you for the suggestion.
     
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  5. urbanrifleman

    urbanrifleman Site $$ Sponsor

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    Please post your results. I am doing a workup with Ar Comp in 6bra and 1-7.5 Brux this week also.
     
  6. urbanrifleman

    urbanrifleman Site $$ Sponsor

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    Try this :)

    Make fire rounds in three bags. 15 shots total. At that 29.3 load. Take one bag and put it in a insulated cup with with ice covered in salt.

    Take another bag and put it in the oven at 130 degrees. Place in another cup with a heat pack.

    Take all three to the range and shoot them over the chronograph.
     
  7. gunsandgunsmithing

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

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    Go straight to imr 8208...about 31.5 grains and work from there. You'll probably find sweetness around 32.0. IME, from light touch to about .015 jam is the sweet spot for seating depth. Benchmark is another good choice. N135 can work but it's not the powder that I thought it would be in that combo. YMMV in that regard as it should be a good choice, if you judge by burn rate alone.
     
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  8. urbanrifleman

    urbanrifleman Site $$ Sponsor

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    Interesting. I have never gotten them to shoot consistently jammed.
     
  9. Poor Shot 65

    Poor Shot 65 Silver $$ Contributor

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    Absolutely - I will keep on posing my results on load development for this rifle. I also have to do load development on a sako-trg 6.5 creedmoor as well .. th
    I live in Henderson (next to Vegas)... so i am basically already shooting in an oven :)

    Thanks

    Adam
     
  10. swadiver

    swadiver Silver $$ Contributor

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    jam 'em .015", if 30 grs of N135 doesn't work, try 32.2 grs. works great for me either load with the 80's in a 12 twist Brux 6BR.
     
  11. swadiver

    swadiver Silver $$ Contributor

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    80 Bergers with two groups of 68 Bergers as well. all 5 shots at 100. 29.9, 32.0 and 32.2 grs of N135 with the 80s. DSC06953.jpg
     
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  12. Poor Shot 65

    Poor Shot 65 Silver $$ Contributor

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    Any idea of what the speeds were of the 80s ?
     
  13. gunsandgunsmithing

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

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    I very rarely find jumping to provide best accuracy, with anything. YMMV.
     
  14. swadiver

    swadiver Silver $$ Contributor

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    let me check to see if i

    let me check and see if i chrono-ed them
     
  15. KMart

    KMart Gold $$ Contributor

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    I agree with Mike and 8208. Light jam. Another combo that with the 80's that worked well was about 30 gr of LT-32 and a light jam. If I remember correctly the velocity with both was around 3150.

    You need to do a seating depth test between touch and .015. It is really amazing how much .003" change in seating can improve groups.
     
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  16. urbanrifleman

    urbanrifleman Site $$ Sponsor

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    Well if he does that seating depth test I told him to do I guess we will find out!!
     
  17. gunsandgunsmithing

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

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    YMMV!! Do what works for you.
     
  18. SS GO DEVIL

    SS GO DEVIL

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    30.5 Varget and Jam .010.
    3130 FPS. Bughole all day and low sd.
    1:8 Twist Krieger No turn neck
     
  19. SPJ

    SPJ Gold $$ Contributor

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    This is Somewhat of an OCW test but in a vertical format whereas Iā€™m only looking at the location of impact and not concerned about the shape of the groups. With that in mind 29.3 area appears to be decent place to start a seating test OR I could go up to the bottom of the next node for a seating comparison. ( shot #5)
    But what do I know.....:D
     
  20. swadiver

    swadiver Silver $$ Contributor

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    approx. 3115 fps from a 24 inch barrel that was the 29.9 gr load. didn't chrono the 32.2 load
     

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