Chronograph integrity Questions

[cosmic]

I believe most measure the time between two shadows across the photo sensors.. Air is clear..(unless your in LA !)

[Ribbonstone]

So the actual speed shown would be for the center distance between the two sensors...admit,  that's not much difference.

If you trust a ballistic program to reasonably project your pellet's path (and vel.) down range....can't you trust it to reasonably  project the difference between 1 yard and Zero?

[SC_RV6A_Pilot]

My FX and my Caldwell are within 2-3fps of each other when the gun is tuned.

Ya, I'd call that good but say they were 20. Then you'd have to wonder what's up and what the correct one . Now your looking for a 3ed to prove one of them with in a fair +/-

How much +/- between 2 would you feel ok with?

Actually, there is already a you tube video where someone does just that using a Caldwell, the FX and a Lab Radar.  The Caldwell, Lab Radar and FX were ALL close.  See this youtube video at about the 4min mark.