Please Help with these Chronograph numbers

generalquark

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Hi,
I went out the the range Sunday for the first time with a new chronograph to see the velocity on my handloads. Since I have never done this, I was kind of curious how consistent the numbers should be. I shot 10 shots and they were as follows.
2406
2402
2376
2355
2376
2402
2411
2372
2376
2372
Is this normal to get this much of a difference? I see that there is a 56fps gap between the highest and lowest. If this is not normal, is it most likely due to an uneven powder measurement? It was a very sunny day, but i thought that as long it is giving readings in the area I was expecting, that it was working fine. Thanks for your help!
 

fx77

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    Re: Please Help with these Chronograph numbers

    If it was factory loaded ammo looks pretty normal.That is a reasonable spread
     

    Enios

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    Re: Please Help with these Chronograph numbers

    Not that unusual. For me the chrony is an excellent tool and a must in reloading though I only see one other at the range besides mine and my brothers. He watched us tune or loads and saw what we were looking at and asked a lot of question and went out and bought one for himself.
     

    InTheWeeds

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    Re: Please Help with these Chronograph numbers

    Unless you are meticulous with your loads, thats not too bad. That could be anything from temp variances (both internal and ambient), powder charge weight, neck tension, bullet weight, and on and on..
    The best minimal spread in a 10 shot string I have ever managed was 11 fps. On average, Im about 20-25 fps spread.
     

    Fred_C_Dobbs

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    Re: Please Help with these Chronograph numbers

    The SD is about 18.8, which isn't bad.

    The thing about reloading is it pretty well adheres to the law of diminishing return (if not the 90/10 rule). Reducing that SD by half probably will require 4x as much money, time and effort.
     

    generalquark

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    Re: Please Help with these Chronograph numbers

    Oh,
    Well you all surprised me with your replies for the good. Thanks for the reassurance, and taking the time to reply.
     

    vman

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    Re: Please Help with these Chronograph numbers

    Fred, you business man you!

    Seems okay to me.

    Depends on a few factors, the main ones being the actuall chronograph used and the standards to which you reload.

    If you used an Oehler (is that how its spelt) chrony, and prometheus to throw charges... then you would expect the spread to reduce

    Internal case volume will also play a part as will consistant neck tension and consistant seating depth.
     

    Moof

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    Re: Please Help with these Chronograph numbers

    I use a CEDM2 with IR's. A buddy of mine uses a cheaper $90. chrono and our number's are different. He shot through his chrono then shot through mine and now he's thinking of getting a much better one that he has now. Also the sun will play hell on your chrono/numbers... that's why I went to IR and never looked back.
     

    vman

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    Re: Please Help with these Chronograph numbers

    Yup!

    Spewing i went out got a master chrony... its ok, but i was telling myself before hand to go with the CED.. anyway, couldnt find one at the time i wanted it, and the funds werent available for the CED...

    sigh

    Buy once, cry once IMO
     

    Enios

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    Re: Please Help with these Chronograph numbers

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Moof</div><div class="ubbcode-body">I use a CEDM2 with IR's. A buddy of mine uses a cheaper $90. chrono and our number's are different. He shot through his chrono then shot through mine and now he's thinking of getting a much better one that he has now. Also the sun will play hell on your chrono/numbers... that's why I went to IR and never looked back. </div></div>

    My question here is how do you know which one is right? Does more money mean better response. I do know shadows will throw different reading. I have a Master Alpha Chrony and little brother has a CedM2 and side by side comparison we had about 30fps spread on average. How many times do you not have that much ES when shooting a group. We didn't think we were leaning much that way so we set them up back to back and the largest difference we got was about 8 fps and that could have been from the bullet going across pick ups at a slightly different angle. Don't get me wrong I love all the bells and whistles on the CED and the fact it will store a ton of information but I still record my info on paper and transfer it to the target for later refrence.....they also make the IR's for the Chrony and you are correct the readings are much more consistent because it will get a more consistent light source.


    http://www.shootingchrony.com/products_newproducts.htm
     

    vman

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    Re: Please Help with these Chronograph numbers

    Enios, not sure exactly why, but it could the minor differences between models that account for the variations in spread.

    I know that the high end chronys can utilise 3 sensors which will increase the accuracy of the unit. I also think that the distance between the sensors can play a part as well.

    I think, in this hobby of trying to elimate as many variables as possible, if you spend the money on reloading gear and invest the time into making finely consistant hand loads, then another variable MAY be to purchase a unit thats known to be of a higher quality.

    If all chronys where spot on with their readings, there would be no market for Oehler chronys... true?

    http://www.oehler-research.com/
     

    Moof

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    Re: Please Help with these Chronograph numbers

    I have no clue to which one is right. But I believe the IR screens are the only way to go. I may be wrong and way off but that is just my .02 I to don't even bother with all the "bells and whistles" either. I just jot down the numbers on the target/group and move on. With mother nature and the sun doing some weird shit out and about, I don't want to just blow ammo across the chrono and wonder if it's close or not... So ya in my own lil world more $$$ is MOST OF THE TIME btter.