I was shoot'n at the range one day....
In the merry merry month of June...

Shooting a ladder test with 243 and 30-06.
10 shots each. Every shot from the 243 failed to register (mostly err1), 8 out of 10 had good readings from the 10-06. All shots were alternated between rifles. Does anyone have any ideas what might cause one caliber to miss every time?
TIA
Gene

different shape rifles? I have two otherwise identical rifles, one short action, one standard length. Every time I change over, I have to move the bags to align.

The other possibility is that you shot at different targets for the two rifles, and one moved you just outside the first eye reading area (i.e. err1). HTH, Dutch.

Way back when I had a Chrony I had the same problem with the small calibers. Always with a 22-250 and frequently with the 243. I called them and was advised to paint the bullets black with a Marks-a-Lot. I did and it helped some. It's a product of the light conditions, it's angle in relation to the reader, and the size of the projectile.

Maybe put the diffuser screens on?

When experiencing such problems, I learned to shoot the smaller caliber bullets in a shaded area over the chrony. I leave the diffusors off of it.

Shade means setting it up either under trees ( which I go out in the woods and do, and use the hood of the truck for a bench rest).

At the range, the shooting benches have a cover over them. I just wait until it is the time of day that the roof casts a shadow down range.

Since doing this, have had no problems. Error means that the shot was read by one diffuser and not the other for verification.

good luck if you try it.

Several weeks ago someone posted a unique, but simple solution for Chrony F-1's that refused to read: Use the tilt feature of your tripod to tilt the screens away from the sun. Since I often shoot when the sun is directly overhead, I tried this (and with a .243Win. to boot!) and it works: Very few Error 1 messages or lost readings. Try it, you'll like it.

Tilting the Chrony from level will lengthen the path the bullet travels over the sensors, resulting in slower velocities read.

Error readings happen when one sensor port is in shadow and one is not, as the sun moves overhead and the shadows are cast by the diffuser screens, etc.

This may not be the thing at play here but needs to be watched for.

A low angle of sun might have maade the smaller bullets harder to read than the larger ones?

Thanks for the input guys,
Dutch side by side targets at 300 meters. I’ll look for parallax error but I doubt it. Both Remington 700’s.

Bob338, The sun was low in the west and shooting east. I hope I don’t have to paint all these bullets.

Lar45, The screens were on.

Seafire, Earlier in the day may work, I’m trying to avoid the heat of the day.

Paul, Gotta keep it level.

DagaRon, the sky was clear and I’ll pay more attention to shadows now.

Thanks again guys. Got rained out today but we’ll get out soon.

Gene

Shadow or cloudy day is better. Shooting closer to the chrony ports (carefully) will help with smaller bullets. Most errors I get are solved by moving the chrony farther away to avoid interference from muzzle blast.

A friend of mine took his wife to the range when doing some chronograph work. He offered to let her shoot. He had the triangular guides set up to show where the bullet should pass above the ports, and told her to "shoot right though it". She did. Blew the chrony all to hell.

One other thing that you might try is takeing a felt tipped black marker and coloring the whole bullet black. This has helped me when it didn't read the 308 I was checking out for my uncle. I also had to do this in my 45ACP.