1000 yard problems.

Discussion in 'Extreme Long Range Hunting & Shooting (ELR)' started by Lancet, May 5, 2012.

  1. Lancet

    Lancet Member

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    Hey guys I am having some issues with my rifle when I am shooting 1000 yards. The first 2 are right on, then by about the 10th shell I am probably 4' low. Anybody tell me why this is happening??
     
  2. Broz

    Broz Well-Known Member

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    Tell us more about your rifle, caliber, ammo and bullet used and maye we can help.

    From the little info you posted my only guess is heat and a stressing barrel or touching stock.

    Jeff
     

  3. winmag

    winmag Well-Known Member

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    How long did it take to shoot your string? I'm with Broz, sounds like a heat issue, but If there was ample time for cooling, it could be a slight fouling issue. But after only 10 rounds its not that likely. Repeatable vertical string like this, is usually heat, or stress related. It can also indicate inconsistent charge weights, but in that case it would be more erotic grouping in a vertical string, not constantly working in one direction.
    Need more info for a better diagnosis.
    Aside from what info Broz mentioned, try to include things like:
    How repeatable is it?
    -does the group always walk its way downhill?
    -does it only show up at real long range, or is it slightly noticeable at other ranges as well?
    Etc.
     
  4. Lancet

    Lancet Member

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    hey guys, thanks for trying to help me out. i have floated the barrel, i have shot 1000 yards 2 times, and it has done it both times. the group consistantly walks downhill. i have really knoticed it at long range, but i have not tried shooting it at maybe 100 yards to see if it does it there.

    my set up is: *winchester model 70, 270wsm
    *Vortex crossfire 6-24x50 mil-dot/w turret system
    *Nosler 140g Hunting Ballistic tip hand loads, 3067 fps

    the heat is sounding resonable, because as your barrel expands from the heat you get less pressure, and that means less velocity, which would cause it to consistantly start dropping low.

    my shots are placed about 1-2 minutes apart. gun)
     
  5. dragman

    dragman Well-Known Member

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    how heavy is the barrel??? that many shots with a WSM with only 1-2 minutes in between unless your barrel is something over .750 I would say it's getting too hot. I had a 300wby that if you put 3 shots through it an didn't space them out at least 4-5 minutes apart the heat on the barrel could burn your skin. it was a SUPER skinny barrel. I only shoot heavy barrels now cuz of that exact reason.
     
  6. Lancet

    Lancet Member

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    It is a standard factory barrel. Sounds like heat is my issue
     
  7. JeffVN

    JeffVN Well-Known Member

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    Agreed its likely a heat issue.

    I shoot a true 7 WSM for ELR (out to 1,850 yards so far) and for 1,000 yard F-Class. The F-class is roughly 24 shots in less than 18 minutes - at least the way I tend to run my relays.

    My rig has a large contour barrel and shoots with tight elevation from the load over the course of the 24-25 shots. I will say that it does take 3-4 shots before the elevation completely settles in at that rate of fire. Even so, I am not shifting more than 1/2 to 3/4 minute at 1,000 yards as it heats in.

    Jeffvn
     
  8. Lancet

    Lancet Member

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    @JeffVN

    How do you keep the heat down on your gun then? Is your barrel the secret to it?
     
  9. Geezer

    Geezer Well-Known Member

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    I'd agree the standard barrel is heating up.

    I had the same problem with a 300WSM Savage with the sporter barrel trying to shoot F-class. First three or four right on, and then they fell out the bottom. Screwed in a heavier barrel and now the misses are only due to my lack of wind-reading ability.

    A heavy barrel or more time between shots might be the only solutions.
     
  10. 4xforfun

    4xforfun Well-Known Member

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    I just happed to take a look at this thread....4' at 1K!!!. The first time I read it i preceved "four inches" at 1k...figured you were just braggin. :D It's not heat....it's stress...brought on by heat. I would think that you might benifit from a cryo treatment. It was mentioned in an earlier post that ...well.." as your barrel expands from the heat you get less pressure, and that means less velocity, which would cause it to consistantly drop low". Wrong....your BBL does not expand...it swells...the OD gets bigger AND the bore constricts..giving you MORE velocity, not less. I tend to heat things up with factory tubes..just because I don't really care about them...and have never seen anything like four feet at 1K., in any direction.

    In 1K comp we purposely let things heat up to stabilize velocity....as things heat up, velocitys rise and the impacts rise...SLIGHTLY. It is not the temp of the ammo that does it....I lay a round on the loading ramp, and when I am ready to fire, I close the bolt and fire almost simultaniously (sp)..the ammo does not heat up...the FPS increase is from the swelling of the bbl....the outside dimeter gets bigger AND the bore constricts. I have seen it a million times when doing load development using a chrono. If you have stress in part of your tube, it will swell either more or less than the metal around it, causing the bbl to "bend".

    Of course, this is my .02...take it for what it is worth.

    Tod
     
    Last edited: May 16, 2012
  11. 270winshort

    270winshort Well-Known Member

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    I would also agree with the heat issue, but I am also wondering how well does it shoot at a 100 yrds,and what kind of numbers are you getting out of your load, S.D. if your S.D. is not in the single digits this could also be part of your problem as well, if your 100 yard group throughs one low once in a while you could also have a load issue.I have a factory model 70 win that is a feather light and it will hold 1/2 moa at a 1000 shooting a 5 shot string then it needs to cool back down,
     
  12. shortpants

    shortpants Well-Known Member

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    Try it again but this time let it cool down between shots. Do that a few times. If the problem goes away go back and do it again without letting it cool down. If the problem shows back up you have your answer.
     
  13. Lancet

    Lancet Member

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    Wld be my S.D? It holds a sub zero group at 100 yards, ii can make all 3 in a group touch with it.
     
  14. 270winshort

    270winshort Well-Known Member

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    S.D. stands for Standard Deviation, which is the average difference between muzzle velocity from shot to shot Example; 5 shot group shot 1 3125 fps
    shot 2 3250 fps
    shot 3 3200 fps
    shot 4 3175 fps
    shot 5 3165 fps
    This would be an example of a load that has a large extreme spread 125 fps the s. d. on this load would be somewhere around 25 to 28 fps.

    An example of good S.D. would be shot 1 3200 fps
    shot 2 3220 fps
    shot 3 3210 fps
    shot 4 3218 fps
    shot 5 3207 fps
    In this example the extreme spread is only 20 fps which would give you a S.D. (or avaerage) of around 5 fps.

    What this means is your load is tuned and it is going to be much more consistent, I always try to find a load that has an S.D. in the single digits(9 or less)

    When shooting out past 500 yards this will make a differnce, your groups will be better, I would take a load with a low S.D. that shot a 5/8" group at a 100 yards over a load that shot a 1/4" group at a 100 yards with a high S.D.

    Hopes this helps I am not good at putting Sh-- on paper there are others on here that could explain it better if you would like more info you can pm me and I can give you my phone #