5 shot grouping issues, driving me crazy

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by buckbrush, Nov 26, 2008.

  1. buckbrush

    buckbrush Well-Known Member

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    Hi everyone,

    Not new to the forum. I've been trolling for a long time but an issue with one of my guns made me decide to join and ask for help.

    I have a 7 mm Rem mag in a 110 Savage action. I had a heavy varmint Shilen barrel installed. It's 26" long 1:9 twist. I've been shooting VLD 168's and have a consistant issue that is driving me nuts, but I may have found the problem this afternoon.

    When I shoot a five shot group, I am fairly consistently getting a cloverleaf out of three shots, then two fliers about an inch from the nice tight group. It happens with different powders and different charges...but almost always, if I do my part, will group three together then spray two others.

    The stock is just one of those Bell and Carlson Duramax's and I made sure that when I installed it the barrel was floated so that I could slide a dollar bill the length of the barrel. This was fine while the gun was upright resting on the recoil pad, however, when the gun is on the benchrest or on the bipod, the stock will flex and make contact on the right side of the barrel channel.

    Could this be my problem? I can ream it out easy enough but wanted some peace of mind more than anything.

    Thanks guys. Great site by the way.

    Michael.
     
  2. Topshot

    Topshot Well-Known Member

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    GiDay Mate,

    Just accept that your rifle may not be able to group 5 shots into the one hole.

    As your barrel gets hot the internal stresses within the barrel metal cause the barrel to change shape. Some barrels do it more than others.

    My advice is to fire a couple of shots, wait until the barrel cools completely then fire a few more. See if this helps before you start pulling your rifle apart.
     

  3. Nomad

    Nomad Banned

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    What are you doing to prep your brass? Try the 162 Amax
    with IMR 4350 has worked well for us.............
     
  4. KRP

    KRP Well-Known Member

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    A dollar bill isn't enough clearance for the barrel in my opinion, especially with a stock that is known to flex. The B&C is better than the factory Savage plastic piece but it still flexes quite a bit. I also think 5 fairly quick shots from a 7 mag is enough to heat that barrel up and change POI, you don't give a time frame for your 5 shot strings.
     
  5. buckbrush

    buckbrush Well-Known Member

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    The shots were not rapid fire but I usually don't allow the barrel to cool a lot between shots. I'd say the five shots were fired in about a minute and a half or two minutes.

    To prep the brass, I have been neck sizing, deburring the flash hole and trimming to 2.500".

    Thank you
     
  6. AJ Peacock

    AJ Peacock Well-Known Member

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    I'd definitely open up the barrel channel to completely eliminate the contact between stock and barrel.

    Good luck,
    AJ
     
  7. Lightvarmint

    Lightvarmint Guest

    Something to try.......... When testing loads, next time try a mirage shade when working up loads (after the barrel channel is relieved to prevent the stock from changing the barrel harmonics).

    Lightvarmint
     
  8. moombaskier

    moombaskier Well-Known Member

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    Hello, I've had similar issues, Then someone asked me how many shots do I normally get at game? My .02 is if your 3 shots are very consistent you should be happy! 5 shot groups are great, but 1 shot kills are better.
     
  9. Forester

    Forester Well-Known Member

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    Yep. worry more about where the first cold bore shot goes. If it is in that first 3 shot group then I would use 3 shot groups for all load development and not worry about it a bit.
     
  10. J E Custom

    J E Custom Well-Known Member

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    First I would try placing the stock on sand bags just in front of or on the front
    bedding screw every time for 5 shots and not on the tri pod. this should stop the
    tripod from forcing the stock into the barrel.

    If that fixes the problem then you need more clearance between the barrel and the
    stock.

    If none of that works shoot 3 shots and clean then shoot 5 shots and clean if there is a
    lot more fouling with 5 shots that could be the problem but only laping or a new custom
    barrel can fix a bad fouling barrel.

    If the barrel is a light weight conture then it may be just the heating up and to prove
    this shoot one round every 10 min to allow it to cool for 5 shots with out cleaning.

    Find and fix the problem don't treat the symptoms.

    J E CUSTOM
     
  11. MontanaRifleman

    MontanaRifleman Well-Known Member

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    That is reeeeeal quick to shoot 5 shots through a 7mm. I know, I have one. The second shot gets it warm and the 3rd shot gets it real warm if shot that quick. Depnding on air/cooling conditions, I will wait anywhere from 5 to 10 minutes between shots. This very well may be your problem... and I also agree with floating your barrel a little more. Another thing... can you stiffin your forearm by bedding an aluminum rod in it with a bedding compund?
     
  12. Eaglet

    Eaglet Well-Known Member

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    Here is my opinion:

    1: Open the barrel channel until a sheet of paper folded in three places goes in and out real easy, you need this specially using a bipod. The dollar bill test is a waste of time. After shooting the rifle usually you're able to see where the barrel is rubbing the stock and you may have to open it a bit more.

    2: You're asking too much from a magnum to group 5 rounds specially if it's hot. Many long range shooters go for 3 shot groups in their magnum rifles. If it gets real cold out side, then you may get away with it.

    3: Make sure the torque in the action bolts is right.

    Go shoot your rifle and enjoy it!
     
  13. buckbrush

    buckbrush Well-Known Member

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    Nov 26, 2008
    Well,

    I reamed the heck out of the barrel channel. I've got lots of clearance there now. I also waited at least five minutes between shots. Unbelieveable. The already tight three shot groups tightened up a bit and no fliers of any kind.

    Man, that made my day.

    Thanks a lot for all of the help and advice!

    Michael.