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Thread: Chrono help

  1. #1
    Boolit Master Drew P's Avatar
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    Chrono help

    So I have had one of these Caldwell chrono for a while and it would always give bunk readings and I had pretty much given up on it because I was never confident in its performance. Sun, cloud, indoor outdoor never could make a correlation. Did a search on it and found that there was a bad batch of sensors or something and that they were replacing some models. Called them and was happy that they said yes we will send a new one out to me. Well I got it and set it up last night in the shop and took a shot. Reading said 8609. Well, im fairly sure Iím not pushing this round 8600fps so what the hell?! Iím sick of this because Iím in the city and I canít just blast away in my shop to no end not to mention itís a waste and inconvenient.
    Are these chronos Click image for larger version. 

Name:	63F4343C-7182-4DE3-961D-3F60F506879C.jpg 
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ID:	207651just garbage or what?

  2. #2
    Boolit Master Traffer's Avatar
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    I bought one from Amazon about 8 months ago and it has functioned without a flaw. I haven't heard of any bad ones until now.
    AKA hans.pcguy

  3. #3
    Boolit Master NoAngel's Avatar
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    I despise those type of chronographs. I've been using a magnetospeed for a few years now. Worth EVERY penny.
    When dealing with islam one should always ask themselves: "What would Leonidas do?"

  4. #4
    Boolit Master
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    I've got a chrony that gives crazy readings every now and then. I traced the problem to weak batteries! I replaced the batteries and the readings went back to where they should have been in the first place.

  5. #5
    Boolit Master

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    Sometimes indoor lighting and or florescent lights have an affect on them also. A thin piece of frosted plexiglass that covers 8" fornt and back and completely over the screesns stops shadows and bad pick ups. I used 1/8" p;exis glass and sand blasted it to give it a frosted effect for a diffuser on my pact professionals sky screens

  6. #6
    Boolit Master
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    Use a paintball gun to check them if you have one. You can shoot them into a trash can in the garage and it would save a trip to the range too. I have a PACT Professional too and if you shoot too low or high across the screens or it is too dim or bright sometimes you get funny readings. Muzzle velocity should be around 300 fps for a paintball gun. ++1 on the batteries too.

  7. #7
    Boolit Master

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    I bought several cans of pellets all the same lot number and use these and my rws r1 pellet gun to check the set up on my pact. I now have a Lab Radar and its way better since its not dependant on light conditions.

  8. #8
    Boolit Master Drew P's Avatar
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    Quote Originally Posted by country gent View Post
    Sometimes indoor lighting and or florescent lights have an affect on them also. A thin piece of frosted plexiglass that covers 8" fornt and back and completely over the screesns stops shadows and bad pick ups. I used 1/8" p;exis glass and sand blasted it to give it a frosted effect for a diffuser on my pact professionals sky screens
    no fluorescents allowed on my property these days. Shop is all led. Haven’t tried this new unit outside yet but man I’m sure disappointed. I’ll put a new battery in it although I think this one is still like new from the troubleshooting on the last unit.
    Good idea on the paintball gun, don’t have one tho. Would a B.B. gun work?

  9. #9
    Boolit Master Drew P's Avatar
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    Quote Originally Posted by Minerat View Post
    Use a paintball gun to check them if you have one. You can shoot them into a trash can in the garage and it would save a trip to the range too. I have a PACT Professional too and if you shoot too low or high across the screens or it is too dim or bright sometimes you get funny readings. Muzzle velocity should be around 300 fps for a paintball gun. ++1 on the batteries too.
    they run paintball guns at 300now?! Back when I was a kid, when paintballs were new, I thought we were running them a lot closer to 200 and those would still raise a nasty welt on a young boys back!

  10. #10
    Boolit Master Traffer's Avatar
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    Quote Originally Posted by Drew P View Post
    no fluorescents allowed on my property these days. Shop is all led. Havenít tried this new unit outside yet but man Iím sure disappointed. Iíll put a new battery in it although I think this one is still like new from the troubleshooting on the last unit.
    Good idea on the paintball gun, donít have one tho. Would a B.B. gun work?
    Maybe led lights are the problem. I have noticed a high frequency "flutter" or almost a strobe effect when using a dimmer on non dimable leds. I hooked up a dimmer to the non dimable ones by accident and found the curious effect at about 80 to 90% power. It made me think that maybe these things have a non-discernable high frequency flutter when running at full power. I guess you could check it with a high speed camera or an oscilloscope.
    AKA hans.pcguy

  11. #11
    Boolit Master JBinMN's Avatar
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    Quote Originally Posted by Drew P View Post
    Good idea on the paintball gun, donít have one tho. Would a B.B. gun work?

    BBgun works.


    I used my grandboys Red Ryder to test mine, & was trying to figure out things like distance from muzzle & such. That is why you will see so many Errors in the test run below. I use the hookup to my cellphone & then send the data to my laptop to compare the data later when I get home. Here is that Test Run with the BBgun:

    Set: 1
    Created: 19/09/17 12:30
    Description: B.B. test
    Notes 1:
    Notes 2:
    Distance to Chrono(FT): 1.00
    Ballistic Coefficient: 1.000
    Bullet Weight(gr): 0.00
    Temp: N/A įF
    BP: N/A inHg
    Altitude: 0.00
    # FPS FT-LBS PF
    10 332 0.00 0.00
    9 ERROR 2
    8 330 0.00 0.00
    7 323 0.00 0.00
    6 ERROR 3
    5 ERROR 3
    4 331 0.00 0.00
    3 ERROR 3
    2 ERROR 2
    1 ERROR 2
    Average: 329.0 FPS
    SD: 4.1 FPS
    Min: 323 FPS
    Max: 332 FPS
    Spread: 9 FPS
    Shot/sec: 0.1
    True MV: 329 FPS
    Group Size (in): 0.00


    I had bought it back in late Spring, but only started to use it in the last couple months.
    I kind of like mine, but I have not used any other chronometers to know if they would be any better...
    It'll do for me & what I do..

    G'Luck! with getting your to work for ya.
    "If ya don't like my gate, ya don't have to swing on the hinges..." - L. Ackerman ( RIP)

  12. #12
    Boolit Master Drew P's Avatar
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    Tried the ole pumpmaster on it and no luck. 3 bbs and one pellet but nothing registered on it. Maybe I’ll put a halogen work lamp on it and see if that helps.

  13. #13
    Boolit Master JBinMN's Avatar
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    My test was outside of my garage the day I tried it. Partly sunny then, IIRC, but I was in partial shade from a tree. I have used it a few times since & am going to use it again in the next few days. The days I tried it I was out on some public land near me & it was mostly sunny out with just passing clouds. I have not tried it indoors & likely never will as I do all my shooting outdoors.

    I bought the kit that comes with the light bars that would go across where the screens are for low light conditions. I am now wondering if they would help with your indoors situation.. ??? Maybe one of these days I will experiment & try them out in the garage with the grand boys BBgun to see,even though I may likely not ever use them for the "big boys" firearms.
    .

    I really do hope you can get it figured out as it is a pretty good setup as far as I can tell, & the price was reasonable for my budget. If ya don't have the light kit and want to use it in low light conditions it may be worth considering...

    G'Luck!
    Last edited by JBinMN; 11-14-2017 at 09:42 AM. Reason: fixed not to now.
    "If ya don't like my gate, ya don't have to swing on the hinges..." - L. Ackerman ( RIP)

  14. #14
    Boolit Master
    lwknight's Avatar
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    Quote Originally Posted by Drew P View Post
    no fluorescents allowed on my property these days. Shop is all led. Haven’t tried this new unit outside yet but man I’m sure disappointed. I’ll put a new battery in it although I think this one is still like new from the troubleshooting on the last unit.
    Good idea on the paintball gun, don’t have one tho. Would a B.B. gun work?
    The led is a big problem for chronographs. The leds are controlled by a PWM that actually flickers the light set intervals to limit the output. That would totally screw with the chrony.
    Sent from my PC with a keyboard and camera on it with internet too.
    Melting Stuff is FUN!
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  15. #15
    Boolit Master hermans's Avatar
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    Using your chrono indoors with LED external lighting is not ideal at all.
    Constant lighting is vital for consistent results.
    The pellet from a BB gun is very small and the unit can most probably not sense the very small difference in light intensity, especially indoors.
    If you want to use the unit indoors only, remove the sun shades, and mount a pair of incadescent strip lights directly above the sensors about the same height as the sun shades, I think they are used a lot in RV's. They work off 12V DC, so and you can run them off any battery or linear 12V DC power supply with good smoothing.
    This should solve your problem when using the unit indoors - good luck!

  16. #16
    Boolit Mold kingrj's Avatar
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    Unless the LED lights are on a battery or filtered supply they will play hell with the crono...The detectors are phototransistors that are coupled to an operational amp set up as a differentiator so it only amplifies high rate of change light intensity....if the led lights are actually pwm (pulse width modulated) controlled then that is the problem indoors...Try it outdoors...I have had great luck using the Competitive Edge Dynamics light screens with a chrono of my own design...The already have the differentiator amps built into the screens and screens cost about $60...They work very reliably for me..

  17. #17
    Boolit Master Drew P's Avatar
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    Ah ha okay. Must be the lighting then. I had heard about the fluorescent issues but not leds yet. Let me do some experimenting and get back with y’all. Thanks.

  18. #18
    Boolit Master hermans's Avatar
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    Please keep us posted on your progress, would like to know if my tinkering with chronographs for the past 40 years is worth anything!

  19. #19
    Boolit Master


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    Also, when you set it up how far from the muzzle is the start scree? Your errant readings in 1st post sound like muzzle blast interference.
    Larry Gibson

    ďDeficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.Ē
    ― Nikola Tesla

  20. #20
    Boolit Master JBinMN's Avatar
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    My light set came in the kit, but below is the light set at a couple of places, if ya don't already have them & want them. Or, don't want to make some yourself as was suggested above.
    Just posting about it in case you, or someone else did not know about them for some reason.


    https://www.amazon.com/Caldwell-7211.../dp/B00HX46M0I

    https://www.midwayusa.com/product/10...raph-light-kit (< Currently OOS/backorder Ok aat this one.)

    G'Luck!
    "If ya don't like my gate, ya don't have to swing on the hinges..." - L. Ackerman ( RIP)

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