Low light and Chrony Chronograph

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DesertRatR

New member
I generally chronograph (Chrony Beta model) in bright sunlight. I have rarely had an error reported. The other day I got out to the range about 2 hours before sunset and set the chrony up in a shadow. The range faces east and I was under the overhang. I was verifying a load I have chronographed previously, and that had produced very good results (45 LC, SD about 12 with ES maybe 30 or so). This time they were all over the map. Extreme spreads of over 200 fps and SD 70 or so. When I plotted up a historgram there was no consistency. Judging from how the gun felt, there was nothing unusual with the loads. When I got home I double checked my scale with cal weights. And also my powder throw. Nothing out of whack.

The chrony manual isn't real specific about low light. Does my experience sound consistent with low light behavior of the chrony?
 
It works by "seeing" the shadow of the bullet. If the light angle is low enough the shadow will shift away from the sensor giving rubbish reads.
I'm guessing what it was actually trying to record was muzzle blast, which being bigger had a big enough shadow to record, but inaccurately.
 
They usually work better on overcast days than bright and sunny. But the suns angle can give false readings. I've also noted days when lighting conditions were perfect and I still got nonsense readings. Not often, maybe 2-3 times in the 5 years I've owned it. Some days I just can't it. One of the quirks to using an inexpensive unit.

If I were buying today I might buy something different, but I can live with it. It works well enough most of the time. The good news is that when they work they are at least 99% as accurate as the more expensive units. When they don't work the readings are so far off you'll know it. If it were giving believable, but false readings it could be dangerous.
 
Chrony makes purty good stuff.
Mine is decades old and works well, even after being wounded a few times.
All chronographs are light sensitive to one degree or another.
Just have to figure out what affects it and what doesn't.
Mine works best, as jmr40 sez, on a grey day and can see muzzle blast.
If it can't be placed far enough away from the gun, shooting through cardboard helps.
 
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