Surprising seating depth

Discussion in 'Reloading Forum (All Calibers)' started by mtang45, Jul 10, 2018.

  1. mtang45

    mtang45 Gold $$ Contributor

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    I have been trying to find the optimal seating depth for my 6BR using 105 Bergers. I started at jammed and moved back in .005 increments to .030 but didn't find anything that was at all promising. I finally decided to run the Berger/Litz seating depth test for VLD's. Jammed, .040, .080 and .120. I had already run jammed so went right to the last 3. To my surprise the .080 off the lands shoots bugholes, and it was just verified tonight with a 5 shot group in the .2's

    Has anyone else experienced the best accuracy with what I would consider an extreme jump?
     
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  2. Dusty Stevens

    Dusty Stevens COVFEFE Gold $$ Contributor

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    Ive seen em shoot at zero and not shoot again until .130 off. You just never know
     
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  3. JimSC

    JimSC

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    .224 Berger 80 VLD's shoot best in my rifle at .075 . Here's a .3 five shot group at 100 and I verified at 300 with 20 shots at 2 targets. I did a slight scope adjustment between 1 and 2 at 300
     

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    Last edited: Jul 11, 2018
  4. RDavies

    RDavies Silver $$ Contributor

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    A few years ago when I bought my first throating reamer I decided to have a play with it but when I pulled it out of the barrel it was full of metal chips, oops. It seemed I had taken .130” out of the throat accidentally.
    I decided to blow off the ammo I already had loaded for it and it shot better than it ever had with about .120 jump and 180VLDs. The extra jump finally turned this mediocre barrel into my main F class competition barrel at the time.
     
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  5. alinwa

    alinwa

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    Welcome to the reality of 'theory' VS 'reality' ;)

    There's another thread down below that's talking about how to find "touching the lands" to the exact thousandth, in it I make a statement, something to the effect of "for those who want to play with those settings of .001-.002-.005 off the touching point....this is a good way to find it for some setups"

    And this is exactly what I was getting at. I spent (wasted?) many years dinking around with these .001 increments using VLD's, because I was fixated on short-range BR style "tuning." Chasing that moving target as the lands cleaned up/receded/polished out to no avail FINALLY caused me to start making some (IMO) "gross changes"....... and the light came on!

    Now, when shooting long range setups I rarely make an adjustment under ten thou. And I always start off of a firm jamset, mainly because with some of the conventional 1.5* leade setups and VLD's there's literally 20 thousandths between touching and jam. And some setups shoot good when jumped like a Weatherby.
     
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  6. Fotheringill

    Fotheringill

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    I did the Berger test with a .223. I was also very surprised at the jump that shot best out of the four six shot groups. Then came the fun part, narrowing it down or up in small increments to find the "sweet" depth.
     
  7. snert

    snert Silver $$ Contributor

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    I learned this "exception to teh rule" rule with a factory rem VS 22-250 that shot like poo till I was 35 off the lands, not in the 10 or 5 like everyone said it would shoot. That was years ago and the Redding COMP die was worth every cent to make that gun go from poo to really good.

    Break the rules
     
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  8. Fotheringill

    Fotheringill

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    You have made great advances in alchemy. You have actually turned poop into gold. I salute you.
     
  9. snert

    snert Silver $$ Contributor

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    if that were the case I would be up to my ears in wealth...but as it is...:oops:
     
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  10. Ccrider

    Ccrider Silver $$ Contributor

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    I thought the Berger test called for .004, .008, .012. Am I missing something.
     
  11. BoydAllen

    BoydAllen

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  12. dmoran

    dmoran Gold $$ Contributor

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    @Ccrider
    Your off a decimal point... lol ... attached below is Berger's recommendation.
    However in my experience, it is way to course in increments. Particularly in and/or closely around the lands.


    Berger Seating Instruction.png
     
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  13. mikecr

    mikecr

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    Berger's test is coarse, and excellent. This is where you see that seating is coarse and powder is a finer adjustment.
    After seating (like during brass fire forming), powder develop, and go back to tweaking seating in a window -to shape grouping. All with a chosen neck tension and primer/primer seating. Then mild tension adjustment is even finer for shaping.
     
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  14. dmoran

    dmoran Gold $$ Contributor

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    @mikecr
    If all out best accuracy is not a concern, that game plan may very well work great.
    There is seating nodes just like powder nodes. Which ones are the most accurate are very often never explored.
    Going at seating in course increments, likely you will never see them all.
    Also IME, jump nodes are often larger in size then In or Close nodes, but rarely as accurate.

    PS: testing seating depth during fire-forming is a good way to blow/form inconsistencies between the cases, do to pressure variations (been there, done that).
     
    Last edited: Jul 12, 2018
  15. BoydAllen

    BoydAllen

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    As I understand it, the idea is to identify the best of the coarse nodes and then fine tune it.
     
  16. mtang45

    mtang45 Gold $$ Contributor

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    Yep, I need to fine tune that .080 off but I gotta say that radio station sounds really good! :)
     
  17. dmoran

    dmoran Gold $$ Contributor

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    Yep... and is why some seating nodes/zones never get explored. Hence, why I feel it's to course.
     
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