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Help Was I thinking correctly?

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  #1  
Unread 09-12-2011, 10:16 AM
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Join Date: Oct 2005
Posts: 215
Help Was I thinking correctly?

I was working up a drop chart for a 22-250

Here is the Data

MV 3695
Zero is 100 yds
Sight Height 1.8
52 Grain Custom Bullet
.225 bc at a G1 (Educated guess)

Temp was 80.6
Pressure was 29.92
Angle 2.1 degrees
Altitude 210 feet

I was shooting at 600 yards. Came up 90 clicks (1/8) MOA to give 70 and change inches of up. The shot was 10 inches low but in a nice little group on my steel. Adjusted my bc value to .200 and it now shows a drop of 80.6 inches given the same variables. I was not able to verify as I ran out of time. Is this what you would have done in this situation?

I figured my speed was a given , BC was the only thing not certain. I am sure I could repeat and verify but I want to be REALLY close and take out the "Experiment" if you know what I mean.

I have heard of guys adjusting speed and not BC to get their charts to line up? What do you do? I was taught to adjust BC.
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  •   #2  
    Unread 09-12-2011, 10:22 AM
    Platinum Member
     
    Join Date: Apr 2010
    Location: Allen, TX
    Posts: 2,608
    Re: Help Was I thinking correctly?

    Quote:
    Originally Posted by kweidner View Post
    I was working up a drop chart for a 22-250

    Here is the Data

    MV 3695
    Zero is 100 yds
    Sight Height 1.8
    52 Grain Custom Bullet
    .225 bc at a G1 (Educated guess)

    Temp was 80.6
    Pressure was 29.92
    Angle 2.1 degrees
    Altitude 210 feet

    I was shooting at 600 yards. Came up 90 clicks (1/8) MOA to give 70 and change inches of up. The shot was 10 inches low but in a nice little group on my steel. Adjusted my bc value to .200 and it now shows a drop of 80.6 inches given the same variables. I was not able to verify as I ran out of time. Is this what you would have done in this situation?

    I figured my speed was a given , BC was the only thing not certain. I am sure I could repeat and verify but I want to be REALLY close and take out the "Experiment" if you know what I mean.

    I have heard of guys adjusting speed and not BC to get their charts to line up? What do you do? I was taught to adjust BC.
    Considering that BC was just a SWAG to begin with, then I'd say it's fine to adjust it.

    Shooting varying distances/conditions with accurate inputs, should help confirm your estimated BC.

    -- richard
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      #3  
    Unread 09-12-2011, 12:29 PM
    Platinum Member
     
    Join Date: Dec 2009
    Location: Big Horn Basin, Wyoming
    Posts: 4,320
    Re: Help Was I thinking correctly?

    Quote:
    Originally Posted by rscott5028 View Post
    Considering that BC was just a SWAG to begin with, then I'd say it's fine to adjust it.

    Shooting varying distances/conditions with accurate inputs, should help confirm your estimated BC.

    -- richard
    I agree. Some times when trying to find a really close bc I will take an 8 foot piece of ply wood at 200 shoot a group on a spot on top then back up to 400 shoot a group then back up to 600 shoot another without ever adjusting my sights. this allows me to measure my actuall drops, and change numbers on my program till i match my actual results that gets me really close. it also gives me a visual on spin drift reminds me that it is there and i can verify what it actually is also.
    __________________
    Mike


    " Real elk guns start with the number 3 or bigger and blow two holes, one in and one out." - My Dad
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      #4  
    Unread 09-16-2011, 03:57 PM
    Bronze Member
     
    Join Date: Feb 2011
    Posts: 40
    Re: Help Was I thinking correctly?

    Quote:
    Originally Posted by Tikkamike View Post
    I agree. Some times when trying to find a really close bc I will take an 8 foot piece of ply wood at 200 shoot a group on a spot on top then back up to 400 shoot a group then back up to 600 shoot another without ever adjusting my sights. this allows me to measure my actuall drops, and change numbers on my program till i match my actual results that gets me really close. it also gives me a visual on spin drift reminds me that it is there and i can verify what it actually is also.
    Yep that what I do to TM.

    Shoot at different ranges without adjusting POA to allow for drop, I too want to see where the bullets are landing and then take some messurements and work out how many clicks that relates to on my scope, write it down and just stick it to the cheekpiece of the stock, that way I've got a reference as to how many clicks at that range do I need. Simple but effective enough for me.
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