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  #1  
Old 06-24-2022, 08:14 AM
Barrika Barrika is offline
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Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4  
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Default Erratic chrono data with my old 357 Mag 19-4

After my last Caldwell chrono failed, they gave me a new one free. Great! But now I have two problems with it:

1) Far too many e2 errors. I might resolve this by stabilizing the chrono mount system a bit more...

2) About 20% of my data shows some really HIGH velocities: as in 5182 or even 7789 fps!!! No, there was no decimal point error there. These were MODERATE rounds, hand-loaded meticulously, and the brass/primers/recoil showed NO signs of high velocity.

Is it possible that the small rifle primers I am now using consistently sometimes get a high-vel spark past the chrono far faster than the 140 gr bullet? ( on 7 gr HS-6 powder) THANKS!
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Old 06-24-2022, 08:53 AM
dla dla is offline
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Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4  
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You're too close to the chronograph - try about 10-15 feet.
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  #3  
Old 06-24-2022, 09:51 AM
ken158 ken158 is offline
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Agree with Dla - back off from the chrono so the blast does not affect the readout. Bad batteries also will show some crazy results too.
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Old 06-24-2022, 09:58 AM
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Nevada Ed Nevada Ed is offline
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Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4  
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I have found the 10 feet works for pistols
15 or more for my rifle testing due to muzzle blast
and my 12 Ga. shotgun can work with 3-4 feet, being very careful with open chokes.
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Old 06-24-2022, 10:43 AM
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Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4  
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Are there any tree's in the area that might cast an occasional shadow over the sky screens? This had me scratching my head a few years ago, the wind would blow the limb shadow over the screen just when firing.
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Old 06-24-2022, 11:55 AM
ReloadforFun ReloadforFun is online now
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Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4  
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Maybe I'm not following this well. A higher velocity reewading says the time interval is shorter. Norally when the muzzle flash triggers the start screen, it results in a longer time interval.

Is everyone saying both the start and stop screens are being triggered by the muzzle flask? That would, I believe, give a short time tinterval.
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  #7  
Old 06-24-2022, 06:22 PM
dla dla is offline
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Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4 Erratic chrono data with my old 357 Mag 19-4  
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Understand that the OP apparently joined this board in order to make this single post. I wouldn't put a lot of mental effort into their question until they reply - if ever
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Old 06-25-2022, 07:59 AM
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I agree - step back to 10- 15 feet. The other thing that might be causing false readings are the lighting conditions. Too much or too little sunlight can do that. Play around with the sun shield diffusers until you find out what works the best.
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