Strange accuracy at LR-Thought?

Discussion in 'Reloading' started by Daves762, Dec 5, 2013.

  1. Daves762

    Daves762 Well-Known Member

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    I have two loads developed for my 300WSM.

    #1 is a Berger VLD, 210gr that is .194 center to center 5 shot group at 100yds-honestly.

    #2 is a Nosler 168 Ballistic tip thats about a .75 group at 100yds. Didn't develop this any further as it was planned to by my "shorter range" deer load and .75 moa was good enough.

    I was shooting at a 10" steel gong at 833yds. All ranged with the G7, no wind, nice warm calm day from rock solid prone with bags and everything.

    The 168 nosler was ringing the gong every time, all too easy. Really it was a laser beam.

    The 210 Berger, which is much more "accurate" at 100yds, was missing half the time. They were near misses, but misses none the less.

    Any idea's how this all works out?

    Is it a "bullet go to sleep" thing?

    I am honestly lost on how a much more accurate load, that is such a higher quality bullet, can be all over the place, while the "factory seconds" ballistic tips were 100%........

    Please advise......

    Thanks
    Dave
     
  2. Mikecr

    Mikecr Well-Known Member

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    Is it a matter of grouping -vs- accuracy?
    You talked about grouping at 100yds, but accuracy at ~800
     

  3. Daves762

    Daves762 Well-Known Member

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    How can a bullet that groups small at 100yds miss at 800 when a bullet that groups larger (less accurate) hit at 800?
     
  4. lloydsmale

    lloydsmale Well-Known Member

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    had a buddy who owned a 7mag winchester that would group 3/4 of an inch for 5 shots at a 100 yards and at 250 wouldnt keep them reliably on paper. Something about that gun was causing instability that wasnt noticed until the velocity dropped to a certain speed. Could be that your gun is doing the same with those bergers
     
  5. woods

    woods Well-Known Member

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    Just a thought for discussion cause I don't know the answer:

    Could it be the 210 gr is approaching the limit of what your barrel and velocity can stabilize and once the bullet slows down it is destabilizing whereas the more appropriate weight bullet is maintaining spin and stabilization?

    Are you chonographing the loads and see if you have a large Extreme Spread on velocities? If you did, the lower velocities loads could be losing stabilization.

    Just posing theories
     
  6. MMERSS

    MMERSS Well-Known Member

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    Are you shooting a round gong?

    Are you consistently shooting .2” groups at 100 with the Bergers or was this a one time incident?

    What was your ES?

    Does your precision show more vertical than horizontal at 100 when shooting groups?

    Where I’m going with this is if you have “ranging” errors you are more apt to miss a “round” target than a square target. A good group at 100 means little if all your error indicators are running up and down.
     
  7. Daves762

    Daves762 Well-Known Member

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    Yes the groups are the same each time, wind allowing of course.

    ES is off the top of my head about 30fps? Nothing severe.

    Yes the gong was round.

    I guess I need to shoot paper to see what "group" looks like at that range.
     
  8. Mikecr

    Mikecr Well-Known Member

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    Because grouping isn't accuracy. They have nothing to do with each other.

    Also, slowing/downrange bullets are MORE stable, rather than less stable, until deep into transonic velocities.
     
  9. Greyfox

    Greyfox Well-Known Member

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    It could very be happening just based upon a high ES. I had two loads for my 300WM using 210VLD's. One at 2800FPS that produced sub.25MOA at 200 yards with an ES that was 30FPS. The other load at 2900FPS, .5MOA at 200 yards, and an ES of 8FPS. The difference between the two loads was powder choice, H1000 vs Retumbo in the second load. The second load clearly outperformed the first load at 800-1000 yards by 4-10". A 30FPS ES is high for long range shooting. If your higher velocity BT had an ES advantage, it could account for the better accuracy at long range. Large ES spreads are generally not evident when group testing at 100-200 yards, but quickly rears it's ugly head at long range as the bullet slows down at longer ranges. Just a thought. It may not be the cause of what your but could be worth checking out. IMO.
     
  10. djtjr

    djtjr Well-Known Member

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    I think this is on the right track! Also dont be surprised at what the BTs can do... just because they are cheap they and the amax seem to constantly be more forgiving in terms of loading and accuracy on targets than many of the other more custom bullets
     
  11. MMERSS

    MMERSS Well-Known Member

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  12. BrentM

    BrentM Well-Known Member

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    I am with Greyfox on this. ES is too high and really shows up at 800 yards. That is about .5 MOA or 4". It could be 4" one direction, 4" the opposite direction.

    I was shooting a rifle a few weekends ago that at 100 yards sent several bullets with different grains and types of powder into a tight group. Although I am happy with that, I know for a fact I have just begun developing a load. When I shoot for groups I start at 200. One more example: My 100 yard zero for a 160 Matrix and a 140 VLD with a 240 FPS difference are the same at 100 yards. At 200 yard zero with the 160 the 140 is 2MOA high.
     
  13. Daves762

    Daves762 Well-Known Member

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    OK thanks fella's