Bad Chrony??

[Grmps]

I inherited a Red "Shooting Chrony" with funky black plastic things that go on both sides and you shoot through a apr. 2" x 6" hole, the box had some smoke damage but the chrony was clean and turned right on.

Took it out for the first time to check loads on a 7.62x25 Tokarev. The numbers made no sense
load A -- 4335 , 01222
load B -- 5309 , 1509
Load C -- 7075 , 0057
load D -- _122 (I gave up after that)

Any ideas or is it a boat anker?

[tazman]

IF you were in direct sunlight(not cloudy sky) and didn't have a diffuser shading the pickups sensors, you often get crazy numbers.
The sensors need to be shaded from direct, bright sunlight.
You can get away without on a cloudy, overcast day.
When I lost my diffuser set when I moved, I cut up a gallon plastic milk jug and suspended strips of the jug over the sensors. Worked like a champ.

[pworley1]

You might be too close to it.

[mattw]

I see that when I am to close to mine! Had a 32acp the other day reporting 3212 fps! Moved back, problem solved. I do not know what it is trying to measure at that point... burnt powder column, invisible shock wave (sub-sonic to boot) or what.

[Kraschenbirn]

I've gotten strange numbers a couple times and repositioning the Chrony out of direct sunlight has made the problem go away.

Bill

[Bent Ramrod]

With my Chrony, I consider a calm, overcast day “chronograph weather.”

If that isn’t in the offing, I wait until the sun is at such an angle so the roof over the line shades the Chrony screens and diffusers.

If that isn’t going to happen, taping a target over the screens to provide extra shading removes the “Error” messages and the 4000+ ft/sec readings. I curve the outer edges down so stray light doesn’t come in from the side.

[country gent]

On my old chronograph that used the sky screens I tried the factory shades/diffusors over each sensor they were about 3" wide and would get errors in some light conditions. I made a one piece diffusor from thin plexi glass that over hung the front and back of the screens by 8" and covered the unit. I bowed this by heating it in an oven and bending forming then sand blasted it to diffuse the light coming thru this worked much better for me out doors.

[metricmonkeywrench]

Grmps send me a PM I think I have the similar model and may be able to help out