Need help/opinions on my load.

Discussion in 'Reloading' started by rfurman24, Oct 9, 2011.

  1. rfurman24

    rfurman24 Well-Known Member

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    Aug 29, 2010
    This is a 7mm WSM built on a long action. COAL is 3.050 .010 off the lands with a Berger 180. I worked up with H1000 and H4831SC until I got less than .5 moa. I have shot 5 three shot groups with 66gr H4831SC in the .3 moa. Here is my problem/concern, four of the 3 shot groups had an extreme spread of less than 10 within the group the fifth had an extreme of 18. The total extreme spread of all groups is 100fps. If I remove the two groups shot with new brass the extreme spread drops to 40fps. All the groups were shot on different days in near identical conditions. I am finding it hard to believe statistically that my chrono is telling the truth. I would find it easier to believe if my extreme spreads within a group were 40fps and group to group extreme spread was more consistent. My next step is to continue taking chrono data and start moving out in distance while noting vertical dispersion as well as checking point of impact against my ballistics app. I would like to hear your thoughts.
     
  2. RockZ

    RockZ Well-Known Member

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    Mar 10, 2006
    Chrono's often will give different velocities on different days in different conditions.
    You can drive yourself crazy comparing data from different conditions.
    If you feel like you have a good load:
    Shoot 5 shots at 500+ yards and check your vertical dispersion as you mentioned.
    That will eliminate all doubt.
    If you have 1" or less vertical , your velocity ES is good.
    Even if you have a great group at 100yds you can still have 40fps ES.
    I've shot .2" groups at 100yds and then shot at 600 and had 6" vertical.
    Check out this link:
    http://www.longrangehunting.com/forums/f28/ladder-testing-1k-detailed-article-video-42881/
     

  3. rfurman24

    rfurman24 Well-Known Member

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    770
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    Aug 29, 2010
    Well I have shot quite a few groups now at 300-700 yards all have less than .4 moa vertical(most less than .25moa). I still need to shoot at the same target at range on different days to make sure the poi stays the same. I am seeing some horizontal at longer ranges(up to 1moa). I need to spend some more time to see if it is me, a parallax issue, or the wind.