CHrono Woes

[CatShooter]

I have a problem/question...

I have two chronographs.

They are both top of the line, and both are accepted as "standards" in the shooting field.

... and they are 150fps "Different", and I need to know real velocity, not just relitive velocities between loads.

How can one determine which is on (or if they are both off).

Whatever the solution is, it must be tracable to an accurate standard... you can't say "use 22 rimfire ammo" cuz it's not an accurate standard.

Any thoughts?? This is not a not a mental trap, it's a real question/problem...

.

[Mikecr]

I don't see how an optical chrono could be calibrated. I've been thinkin about building accoustic screens(using microphones) for my Oehler. This could be calibrated with a audio frequency standard(like 1khz).
It could trigger off the bullet's shock wave, rather than shadow. Like that used in the Oehler43 system.

It would help if I had a schematic or atleast a technical description of my chrono operation though.

[CatShooter]

[ QUOTE ]
I don't see how an optical chrono could be calibrated. I

[/ QUOTE ]

You need a known source of speed, then you adjust the spacing of the traps so the chrono matches the known sourse. I just can't figure a way to do it.