Chrony Chronographs...

Discussion in 'The Basics, Starting Out' started by TireurDelite, May 6, 2005.

  1. TireurDelite

    TireurDelite Active Member

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    Feb 9, 2004
    Hello,

    Midway has the F1 standard on sale for $69.99 and I was thinking of getting one.
    Has anyone use this model and brand? comments please.

    Thank you for your time.
     
  2. 7Rumloader

    7Rumloader Well-Known Member

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    Jan 20, 2005
    I have and currently am using that brand but I am preparing to upgrade. The masses will agree here (I think) that they are by far not the best around. Look under oehler chronographs and rsi shooting lab I believe in bullets barrels and balistics and you will find some opinions of the shooting chronys as well as oehlers. The RSI is said to be as accurate as the oehler for a little less cha ching! There is nothing wrong with the shooting chrony I have and proves to be right on track with shooting chronys around home but it hasn't been tested beside an oehler or RSI (yet). If you decide to buy it it's a good product and will give you some insight to your reloading but don't be surprised when you list a velocity here and someone asks what kind of chrony you used and then says that seems a bit high when you tell them the brand. Here is my honest opinion save a little more cash and buy either the oehler model 35 with or without the printer or the RSI millenium and don't look back!
     

  3. abinok

    abinok Writers Guild

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    7rumloaders comments are right on.
    The 35 is nice, has the longer skyscreen spacing, in is just all around a better chronograph. Its also $184 compared to $70. I will say, that the 35 at 184 is a better deal than the chrony at $50.
    Theres lots of issues with the chrony, simply due to its design, and its 12" skyscreen spacing.
    If you ar still thinking about buying the shooting chrony, go read this, and save your money...
    http://www.benchrest.com/forums/showthread.php?t=21080
     
  4. ds

    ds Well-Known Member

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    Had the RSI but now have the Chrony F1. The RSI had a lot more features but was a bit of a pain to set up. The F1 is simple, it does what I need that is to give a Fps reading to show if load development is going right or not, the F1 goes with me more often than the RSI used to because the F1 is so compact (downside s shorter distance between sensors). No doubt it is not as accurate as the others but and has none of the other features but it does enough for me.

    David.
     
  5. ricka0

    ricka0 Well-Known Member

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    Good info!
    [ QUOTE ]
    has the longer skyscreen spacing, in is just all around a better chronograph. Its also $184 compared to $70. I will say, that the 35 at 184 is a better deal than the chrony at $50.
    Theres lots of issues with the chrony, simply due to its design, and its 12" skyscreen spacing.
    go read this, and save your money...
    http://www.benchrest.com/forums/showthread.php?t=21080

    [/ QUOTE ]

    The gist of that thread is exactly what trivial math/electronics theory would conclude, all the error comes from spacing.
    [ QUOTE ]
    <font color="brown"> For a 12" screen spacing and 3000 f/s muzzle velocity, the maximum error would be roughly 0.2"/12"* 3000f/s = 50 f/s. .... For a 24 foot screen spacing (288") the maximum error would be about 0.2"/288"*3000 = 2 f/s</font>

    [/ QUOTE ]
     
  6. daveosok

    daveosok Guest

    That is some good info.
    I can see where 50 fps versus 2fs would come into play, extreme spread. I doubt that it is consistantly 50fps dead nuts every time. So you have 50 fps versus 2 fps, I will take the 2fps anyday.
    Good info and thanks for it. I borrowed a 35p and it was the cats meow, been saving for one things just keep showing up where I cant spend it lol. I found the 35p with printer for $315.00 which is really a good price. Have any of you seen it for less anywhere?
    Dave
     
  7. obfmcb

    obfmcb Member

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    I have Chrony and I like it just fine. It depends on what you are after - in my case, I bought one to determine load consistency for my varmit rifles and especially for black powder cartridge rifle loads (shooting for and getting single digit ESD's). I'll probably upgrade to a Oehler at some point, but no rush.
     
  8. abinok

    abinok Writers Guild

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    [ QUOTE ]
    I bought one to determine load consistency for my varmit rifles...

    [/ QUOTE ]

    I bought my shooting chrony for the same reason. The intent of the thread I posted was to show not that the chrony will consistantly show a velocity of up to 50fps faster or slower than actual velocity, but that it does not have enough resoultion to see differances accurately that are smaller than 50fps. This makes it mechanically incapable of giving accurate es and SD data. That being said, with good conditions, the window of accurate velocity resoultion is a good bit smaller than 50fps... at least in my opinion. But it does mean that there is a limit to the resolution, and that this chrony cannot give accurate es or sd figures down to the single digits like the Oehlers will with the longer skyscreen spacings.
     
  9. brian b

    brian b Well-Known Member

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    The very first chronograph that I ever bought was a shooters chrony, it was interesting at first to have a new toy, but after a while it was very apparent that it was just that (a toy) after shooting it 2or 300 times just to make sure it was dead I bought an Oehler 35 and have lived happily ever after owning a tool not a toy.
    B
     
  10. obfmcb

    obfmcb Member

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    I agree that the absolute velocity that you measure will be more accurate if the skyscreens are spaced farther apart. Relative velocities between shots are different story. If I am reading your comments correctly, you seem to be assuming that there is going to be a 0.2" variation in the skyscreen spacing shot to shot, but that clearly isn't the case. Once you are set up, the screen spacing is fixed, the position of the chrongraph relative to the rifle is fixed, and as long as the lighting conditions aren't changing, the only real source of variablity is in the timing circuitry, and that's a pretty simple gizmo. One of the reasons the Oehler is the better instrument is that the timing is measured twice and compared for each shot, and even here the Oehler is going to give you an odd reading every now and then.
     
  11. HoytemanPA

    HoytemanPA Well-Known Member

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    I believe that it is the shot to shot variation that is minimized by the extended screen spacing. I do not believe the timing circuitry is the cause of this type of error but rather the threshold trip point of detecting the bullet in flight. Although the spacing is fixed the detected signal may not be. A .5 inch in variation could be very real if the first light sensor detected the very front, and the second detected the middle of a 1.6 inch 30cal Matchking. Then the next shot had a slightly tarnished bullet or whatever and detected the front on both sensors. By increasing the screen spacing the variation would be lessened because the measuring surface of the bullet is less of an issue. Say 10 feet .5 inch bullet detection error vs 1 foot .5 inch bullet detection error. Which is why as you say even an Oehler will give an odd reading every now and then. Now stretch a "junk" Chrony to 10 feet and......Well I'll let you know how I make out.
     
  12. IanF

    IanF Member

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    Appreciate the thrust of this thread - but a question to follow the last post.

    If you JUST change the spacing of the screens on the 'junk' chrony - am I right in assuming this change in distance needs to be programmed into the software operating the unit - or all mathematical calculations would be meaningless?

    Rgds Ian
     
  13. nowler

    nowler Well-Known Member

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    ian

    if you doubled the distance say, then the output speed you'd be getting would be half of what the true reading was etc. etc. then again it would be roughly half the true speed as chrony's are pretty poor in accuracy terms. just mho. i have a beta master if you want one? i am saving for the ohler /ubbthreads/images/graemlins/grin.gif
     
  14. IanF

    IanF Member

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    Nowler.

    Many thanks - reading your post was accompanied by cries of 'Doh!' and much forehead slapping. /ubbthreads/images/graemlins/smile.gif Makes perfect sense - but keep saving! /ubbthreads/images/graemlins/wink.gif

    Ian