Why so bad grouping???

Discussion in 'Reloading' started by MAHMOODB, Jun 13, 2013.

  1. MAHMOODB

    MAHMOODB Member

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    Hi. I have a howa 300 win mag which i have some issues with. I am reloading 180gr sierras with winchester cases and cci200 primers and s365 powder.
    My problem is at 100metres i get a fantastic grouping of 1/2". but at 200 meters my grouping opens up to 5" and at 300meters its basically all over the show.
    what can be the problem. all the cases are perfectly equall as well as seating depth as well as well as as powder measure.
    iv also tried nosler bullets of 180gr an the result is the same.
    is my bullet too heavy for that distance or ?????????
     
  2. jasent

    jasent Well-Known Member

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    Have you checked your action screws? What stock do you have,Blackhawk axiom? Could be a bedding issue. I have a weatherby vanguard in 300wm in a Blackhawk axiom stock. My gun is real picky on bullet selection but shoots Berger 185gr vld's real well! 1/2 moa out to 500 yards so far. What optics are you using. Could be 1000 different things that's opening your groups. Check your scope rings and mounts first,also are you adjusting parallax properly?
     

  3. Mikecr

    Mikecr Well-Known Member

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    Nope. Stability generally improves with distance.
    Is your scope adequate for precision at distance?
     
  4. westcliffe01

    westcliffe01 Well-Known Member

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    Parallax ? Wind should not be bad for a fast moving 180gr bullet. But seeing your aiming point properly at 200 and beyond can be an issue. I will say that with a 12-16x scope getting a good group at 300 yards is no problem at all.
     
  5. ARTY SGT

    ARTY SGT Active Member

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    Just wondering also...whats your barrel twist rate?
     
  6. jasent

    jasent Well-Known Member

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    parallax is more than just a clear sight picture

    Parallax - And how scopes work
     
  7. westcliffe01

    westcliffe01 Well-Known Member

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    I know what parallax is. Does the OP ? Leupold and just about everyone else still manage to sell a heck of a lot of scopes with no parallax correction capability, and I'm sure the people who use them don't think they are missing anything (excuse the pun)
     
  8. jasent

    jasent Well-Known Member

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    That's why I posted it. To make sure the op knows what parallax is. why would you question my response if you knew. Any one trying to shoot 300yards plus needs to know that info.
     
  9. Clark

    Clark Well-Known Member

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    I have helped a lot of shooters with bad groups over the years, and I am my own most frequent person with bad groups.

    Over 50% of the time, bad groups are caused by loose screws that attach the scope base to the receiver.

    A big clue that is the problem, is when there are two hole touching, and then next two holes touch way over there.
     
  10. baldhunter

    baldhunter Well-Known Member

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    I've run into the same discovery as you.I used to try to get really tight groups at 100yds,expecting them to open up just a little more at 200yds.It is true,some will only open up a little more,but some will open up a lot more.There are many factors working against you as you move a little farther down range.Parallax may or may not be a problem.Rifle bedding can be a culprit too.Human error can be a major factor.It is a little tougher to shoot tighter groups as you move farther out.Heck,just look at how much the crosshairs block out.Bullets can be bad too.Poor dies producing crooked ammo.Wind can start affecting your groups too.The list really goes on and on.
    Some of the things that have helped me,once I've determined the above is not the problem,is play with your seating depth and adjust or try a different load or bullet entirely.These days,I don't spend too much time perfecting my loads at a 100yds,once I find a load that groups well,I then test it at 200yds to see if it still groups well.If it does,see if it's repeatable and not just a fluke.It's the little things that make a big difference.I had one of my favorite rifles that would consistently shoot well under an inch produce a poor 4" group at 200yds.Just adjusting my seating depth by a mere .010,changed the 4" groups to 1" groups.I've also had rifles that would shoot well at 100yds that I never could get to shoot good at 200yds.Those are no longer with me.I think one of the best things to do is,find a bullet you and your rifle both like,work up a load that shoots well and you both will live happily ever after.
     
  11. Ricardo

    Ricardo New Member

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    Ricardo

    Hi I've got the same prob, and I'ved try load 66 with 180g on 100m its sort of ok but 200m there n big prob? plz assist us?
     
  12. jasent

    jasent Well-Known Member

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    What scope are you using? When I work up a load I ladder test at 400 then group test at 300 then zero at 200 and then see what it looks like at 100. Just how I do it.
     
  13. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    Crappy bbl, nothing more, nothing less. Likely stressed or badly fitted. I've seen a couple of m70's do this and a ruger 77. They all shot fine at 100 but went to pot farther out. The scopes were proven on other rifles as the rifles all went down the river and the scopes got other homes. You will likely find your 100 yard accuracy also blows when all is said and done and you've got more than a few groups on with each load.
     
  14. Ricardo

    Ricardo New Member

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    My scope is a Niko Sterling 3x9x42, if use it in my mauser 7x64 and my grouping was fine. start missing my 7x64, og!!! but I wanted a 300 win mag but ja, so I must zero on 200m and start there?