Vertical stringing of shots--suggestions?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by sambo3006, Jan 24, 2006.

  1. sambo3006

    sambo3006 Well-Known Member

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    I tried a new load in my 30-06AI yesterday using a 180 gr SBT. I fired 2 groups at 200 yds and both of them showed less than 1 inch horizontal spread, but the vertical spread was around 4 inches. No, the barrel wasn't getting hot (barely warm to the touch). This gun normally prints .5 MOA with 150 gr BT. I had removed the sling studs to prevent interference with the bags and the gun came straight back in recoil, no jumping. Tried to chronograph, but my old shooting chrony wouldn't register-time for a new one. Don't know if this would be an equipment issue or perhaps a high SD on the velocity? Gimme what you got. Thanks! Sam
     
  2. jb1000br

    jb1000br Well-Known Member

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    Something is horribly wrong...mich more than velocity spread...unless it is like 300fps /ubbthreads/images/graemlins/shocked.gif

    how many shots in the group?

    gun specs?

    load specs?

    heck, maybe your stud was bearing on the barrel and HELPING you?

    JB
     

  3. sambo3006

    sambo3006 Well-Known Member

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    Didn't think it could be SD. This is a Rem 700 LSS with a 25" #5 Shilen barrel. It was pillar bedded and floated by a local gunsmith. 4 shots in each group. The load was 62Gr of RL22 (as per the nosler manual) Rem 9 1/2 primer behind the 180 gr Sierra SBT moly coated seated 10 thou off the rifling. Talked to a friend who has done some stock work and he thinks it could be a pressure point somewhere. This gun has been finicky before. The 150 gr BT load was the most consistent. That might be an idea on the sling stud. Thanks, Sam
     
  4. jb1000br

    jb1000br Well-Known Member

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    I'm at loss on there is something loose, either in the mounts, rest or otherwise.

    I'd see a smith...

    JB
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Sambo3006,

    First thing I look at on a rifle with a vertical stringing problem is the bolt lug contact evenness. Was the receiver trued and the lugs trued and lapped before barreling? Were the receiver threads trued as well?

    If you have a floating lug you will see vertical stringing in the Rem 700 or any other two bolt lug receiver design. Generally, the ligher the load or the lighter the bullets, the better these rifles shoot.

    The higher the pressure or heavier the bullet, the more bolt thrust is created and there is more bolt flexing resulting in more vertical stringing then with lighter loads or bullets.

    Check the bolt lugs out first.

    Also, look in the receiver and make sure the barrel bolt nose recess in the barrel is clean. If there is something in there making contact between the barrel and bolt when locked up you will get accuracy issues as well so make sure this area is clean as well as the bolt nose.

    Check your receiver screws and scope base and ring screws. If your using a windage adjustable scope base make sure the rear clamping screws are holding the rear ring securely.

    Did you see any difference when shooting starting loads compared to upper end loads. If you did, I would certainly look at the bolt lugs. This should not happen with a properly trued receiver so let us know some details as to the original rifle build process. What was done to the receiver.

    A finicky rifle is generally due to issues in the receiver and barrel machining but can also be as simple as something wedged in the bolt nose recess of the barrel.

    Let us know,

    Kirby Allen(50)
     
  6. sambo3006

    sambo3006 Well-Known Member

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    I'm going to check all the screws tomorrow. When the gun was bedded (with the original factory barrel) the gunsmith lapped the bolt lugs, but I don't believe he did anyting more than that. I have gotten some very small groups with the ackley barrel but this is the first time I have tried heavier than 150 gr bullets. To my knowledge, nothing special was done to the receiver when the new barrel was put on. Hopefully something has just come loose somewhere. I'll check where the barrel meets the bolt face for any debris. I'll update when I have the chance to shoot it again. Thanks! Sam
     
  7. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    May just not like heavier bullets. Can't make a rifle shoot what it does not like, simple as that I guess!!

    Kirby Allen(50)