do i trust my chrono or group size?

Discussion in 'Reloading' started by shawnb, Oct 22, 2012.

  1. shawnb

    shawnb Well-Known Member

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    this group was shot off bipod prone with my fist as a rear bag at 185 yards. its a 7mm rem with 70gr H1000 215M primers .03 off. not to bad a think. i had a group yesterday with this load that looks the exact same.

    chrono yesterday read between 3030-3044 with 3040 average 14ES and 5SD between 5 shots. 2 shots duplicate and another 2 duplicate. today my chrony read the five shots between 2995 and 3058. i havent been able to shoot farther but just wondering what to go with. it will be a while before i get to shoot farther.

    the chronograph is a Competition Electronics Prochrono electric.

    any thoughts?
    PS. the group is 1.25 horizontal not vertical. i cant get the photo to rotate.
    photo.jpg
     
  2. brentc

    brentc Well-Known Member

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    I've got a Prochrono too, and I've noticed it is sensitive to light changes. Sunny, cloudy, back to sunny type of changes. The changes affect the readings.

    The only way you'll truly know is to take your loads out further, or get out on a day that offers consistent light conditions. I'd be willing to bet that you have a consistent load, and that something is causing your chrono to misread.
     

  3. Codyg510

    Codyg510 Member

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    Second on the chrono misreads. If you're happy with the accuracy head on back 700-1000 yards and true the trajectory when you get a chance. I know not everyone has 1000 in their backyard, but it's def worth doing. If your vertical stringing is really tight at these distances then you know your load is consistent. 14ES and 5 SD is pretty awesome.
     
  4. shawnb

    shawnb Well-Known Member

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    ya i guess the light conditions were very different. today was very overcast and -5C. i also left the diffusers on which might have also affected it. yesterday was around 5-10C and sunny with cloud cover when the shots were fired. i was pretty happy with the group. the last 2 shots were the ones on the outer edges. but thats not saying much considering the fist rest i was using haha.
     
  5. kaseyfied

    kaseyfied Well-Known Member

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    Trust your group.. I had great groups and terrible reading on my chrono sometimes tilk I bought the m2 chrono with the inferred option and have.never looked back. I csn shoot whenever and where ever and it reads true.. Well worth the money.. But trust your groups.. Not the chrono myfriend
     
  6. Joe King

    Joe King Well-Known Member

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    +1 you know how you shot and that paper isn't gonna lie.
     
  7. green 788

    green 788 Well-Known Member

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    I tell all my folks... the target is the final arbiter.
     
  8. Time Killer

    Time Killer Well-Known Member

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    In the case that your chrono is inconsistent, how do you guys get your dope for later shooting if you do not have access to a longer range at that time??
    Warning, could be a dumb question...
     
  9. kaseyfied

    kaseyfied Well-Known Member

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    Even with an accurate chrono u need to shoot and see what your rifle does with your bulket powder combo.. u can get in the ball park with published load data but i would not just use that and go hunting..