Suggestions how to tighten up this group (if any)

Discussion in 'Reloading' started by RocketDog, Mar 26, 2015.


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  1. RocketDog

    RocketDog Active Member

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    Just started getting into reloading and was wondering for some opinions. I'm shooting a Ruger M77 Mark ii 7mag with Berger 168gr VLD hunting bullets, H1000, Federal Brass and Winchester Mag primers 100 yards. The first batch was made to figure out my powder charge. Started at 68.8 and worked up .4 grains to 70.4 seated them all at to the same ogive length of 3.465(not subtracting the comparator). I had consistent point of impact on powder charges 69.2, 69.6, and 70. Picture below on the left is of the best group from this batch at 69.2gr.

    I then moved onto seating depth using 69.6 grains of powder. I went up .005 starting at 3.465-3.485 ogive. The best group was at 3.485 pictured below on the right.

    Any suggestions on how to tighten it up from here? I realize its just a Ruger but would like to see if I can get a tighter group.
    Thanks
     

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  2. brentc

    brentc Well-Known Member

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    Keep your seating depth and test 69.4 and 69.5 to see if it tightens. Or, just load 69.4 grains and run it. I doubt you'll get much better results than what you're seeing in your posted targets with your factory Ruger.
     
  3. RocketDog

    RocketDog Active Member

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    Ok I'll give that a try.

    More on the gun, it's been glass/pillar bedded, floated barrel, stoned trigger, added a holland break, Harris 9-13 swivel Bi-pod, and have a Vortex Viper HSLR 4-16x50 mm FFP.
     
  4. FearNoWind

    FearNoWind Well-Known Member

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    That group on the diamond looks to be 1/2 MOA. Assuming these are 100 yard targets, for an "off the shelf" rifle that's really pretty good. Since you've already done the mechanical work mating the stock to the action the only thing I can suggest is holding the seating depth where it is and work with minor load adjustments.
     
  5. LoneTraveler

    LoneTraveler Well-Known Member

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    With a new factory rifle barrel good groups. When you clean the barrel, If there is any bullet jacket residue coming out of the barrel, May be the problem. Either being patient shooting and cleaning the barrel may help. Or fire lapping or pour lead barrel lap may help the rifle. The only other thought would be change bullet weight up or down 10 grains to better match the bullet to the barrel twist.
     
  6. Korhil78

    Korhil78 Well-Known Member

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    I would take both groups and shoot them at 300 yards and see what they do. If your load is consistent, I would say that the load on your right picture will be the best as it has less vertical but to really test the vertical spread, you need to shoot further out.
     
  7. Bill Johnson

    Bill Johnson Well-Known Member

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    I think that's the best way to proceed, and shoot 5 shot groups. As they other guys pointed out, you're doing pretty darn good for an off-the-shelf Ruger. The longer range, 500 would be better, will give you a much better idea of where you can improve the load.
     
  8. Punisher

    Punisher Well-Known Member

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    berger claims that the seating depth sweet spot is 25-40 thousands deep once you find it. So it looks like you are there. Now change your powder charge, or primer.
     
  9. Mikecr

    Mikecr Well-Known Member

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    I think you messed up in your approach.
    The reason best seating suspiciously seems close to where you had pulled it out of your butt is that anymore change to seating would take you out of your best powder load(seemingly making things worse). It's 2 changes at once(at least).

    It could be better(could be) if you had tested seating, full blown, with Berger's seating testing method(pinned here) at a reduced charge, far from any powder node. Could have done this while fire forming brass.
    Then move into powder testing, then tweak seating inside of 10thou to shape grouping(which is all you're doing now).
    Just a suggestion. You got nothing to lose.
     
  10. gohring3006

    gohring3006 Well-Known Member LRH Team Member

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    I have a TC Venture 30-06 that was shooting 3/4" which was satisfactory, then I tried a different powder and got a good rear bag and it turns out it shoots in the .3s. A powder switch sometimes is the answer. Also I had a load that shot 1moa and switched primers and viola!!!!
     
  11. Mikecr

    Mikecr Well-Known Member

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    It's difficult to describe how abstract load development can get...
    An actual procedure seems hopeless
     
  12. RocketDog

    RocketDog Active Member

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    Ok thanks. I'm going to make 5 rounds seated at the same length and shoot them at 300 yards.
     
  13. Bill Johnson

    Bill Johnson Well-Known Member

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    Wow, Mike! that's so funny........but so true. You could go in to ogive comparators, primer brisance and powder columns, any number of possible variables. Bench technique (shoot 22RF at 200 and you'd see how bad you really are).
     
  14. Bullet bumper

    Bullet bumper Well-Known Member

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    Berger's procedure seems to make little sense to me. It is accepted that VLD secant ogive bullets don't like a jump to the lands so why try them at .150 from the lands.
    Seems to me to be about wasting bullets which means you have to buy MORE.
    I would start with the bullet just touching the lands and go from there .
    You don't want to jam it in too hard as you may pull the bullet out upon extracting an unfired round. The real sweet spot is from just touching the lands to the deepest you can go and not jam the projectile on extraction . You may be able to get good results not touching the lands but it's not going to be way off the lands so what Berger is saying is ridiculous.