6.5 CM 7.5 twist: which bullet weight?

Oldmauser

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I have been shooting 140gr bullets all the time(huge stockpile). I don't really have a benchmark to follow. I achieve sub moa accuracy at 100m, but it's clearly not enough. Is changing to 147/150gr the way to go in terms of tightening my groups?
 

Steel head

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    147 is fine with 1-8
    Under spinning them is generally the key for tighter groups.
    Over spinning is for transonic and subsonic performance.
     

    shoot4fun

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  • Oct 27, 2003
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    Maybe it isn't the bullet/twist combo that is the issue. Could be you just don't have the load quite finely tuned.
    I have always felt the 6.5 bullets (all of them) don't need the 7.5 twist. I'm shooting 153 A-Tips in my 6.5 PRC and see no problem with 1,000 yard groups.
     

    Oldmauser

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    I was tempted by my gunsmith to try "the new better twist":).
    I was hoping that some of SH users could share their experience with 7.5 twist in terms of optimal bullet weight.
     

    Steel head

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    I was tempted by my gunsmith to try "the new better twist":).
    I was hoping that some of SH users could share their experience with 7.5 twist in terms of optimal bullet weight.
    Most don’t bother with the 7.5 especially with 140’s.
    40007EE6-0E03-4B52-9EBC-4B12A32A8641.jpeg
    140 grain bullet with 1-8.
    I’ve burned down a few 6.5 barrels now as for as I’m concerned 1-8 is the secret sauce.
     
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    Ccollins02

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    I started going with 1:7.5 260 barrels with the thought of trying 147s. I ended up never running them, but instead ran 130s. The 130s in my 7.5 Bartleins have been the most accurate 6.5 combos I’ve ran. There’s a lot of variables involved for accuracy beyond barrel twist and bullet weight...
     

    Steel head

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    I started going with 1:7.5 260 barrels with the thought of trying 147s. I ended up never running them, but instead ran 130s. The 130s in my 7.5 Bartleins have been the most accurate 6.5 combos I’ve ran. There’s a lot of variables involved for accuracy beyond barrel twist and bullet weight...
    I’d be worried about blowing up 147’s with 7.5.
    my 1-8 had plenty of problems with them.
    As far as correlation of 130 and 7.5, you just got a great barrel and can utilize it but I think you already know that.
     

    Ccollins02

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    I have shot some 130 ELDS and wasn’t disappointed. But the Berger AR hybrids are what I typically run, they’ve been fantastic bullets for me.
     

    hereinaz

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    Depending on the distances you are shooting, the extra velocity on the 130s outperforms the higher BC of the 147s. I would not be afraid of running 130 or 140s.
     

    308pirate

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    I have been shooting 140gr bullets all the time(huge stockpile). I don't really have a benchmark to follow. I achieve sub moa accuracy at 100m, but it's clearly not enough. Is changing to 147/150gr the way to go in terms of tightening my groups?
    Load development isn't as simple as that.

    What have you done to fine tune your current load?

    The common question of "what's the best twist for X bullet" implies a shallow understanding of how to maximize accuracy.
     

    308pirate

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    Yes, sir. That's why I post my question on SH, so I can improve my understanding of accuracy.
    If you look at the post you took that quote from, you'll see that I asked what have you done in order to fine tune the accuracy of your handloads.

    The conversation is much more productive if we understand what you've already tried.
     

    beersngars

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    Just yesterday I finalized my 6.5 Creed load using a Kreiger 28" 7.5 twist barrel. I'm using 147 ELD's at 2828 and shot 3 sub 5" groups and several sub 7" at 1000yds. The conditions were excellent. Very happy with the results.
     

    soap11x

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    130 ELD is what I'd try. I'm getting solid groups consistently. However, can't promise you that you will drastically improve the sub-moa groups.
     

    XLR308

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    My 65CM wears a Bartlien 5R 7.5" twist finished at 23" (Breach face to crown) and shot everything from 123CC , 130 Hybrids, mostly 147eldm and some 150smk.
    The only one that I haven't tried to tune perfect for the rifle is the 123CC since I mostly use it in the 6.5x47 I really don't think the extra twist is needed until you get to a bullet as long as the 150smk but it doesn't seem to have any negative effects with the lighter and faster 130 class bullets.
     

    stello1001

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    My 65CM wears a Bartlien 5R 7.5" twist finished at 23" (Breach face to crown) and shot everything from 123CC , 130 Hybrids, mostly 147eldm and some 150smk.
    The only one that I haven't tried to tune perfect for the rifle is the 123CC since I mostly use it in the 6.5x47 I really don't think the extra twist is needed until you get to a bullet as long as the 150smk but it doesn't seem to have any negative effects with the lighter and faster 130 class bullets.
    I'm surprised you didn't blow up the 147s. Others seem to blow them up occasionally on 8 twists...
     

    Steel head

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    130 ELD is what I'd try. I'm getting solid groups consistently. However, can't promise you that you will drastically improve the sub-moa groups.
    I went from the 147’s to the 130’s.
    Flatter trajectory at the ranges I run that rifle at now.
     

    jtackmann

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    My hawk hill 7.5 twist likes 140g eld the most by far. Generally .4 groups with an odd .6 here and there.
     

    Steel head

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    Would that happen to be inside 1000 yards? Did you notice a huge difference in windage?
    Out to 1200-1300ish Is where that rifle is designated for.
    Wind is very similar but it’s flatter and softer shooting.

    Back when that rifle had to cover everything I ran 147’s.
    Then two things happened.
    First newer production 147’s starting blowing up and second I built a rifle for further distances so I re tasked the 260 for the inside stuff and for friends to shoot.
     
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