How accurate is your chronograph?

[jps2486]

And why would it matter - it’s not like a slightly out-of-spec chronograph is going to mean much. Our ballistic models are still only approximations and shot to shot variance is much more significant.

To the Brits it does. If your rifle shoots 12.01 fpe, you will go to jail.

 

[Hateful McNasty]

To the Brits it does. If your rifle shoots 12.01 fpe, you will go to jail.

On what " calibrated" precise chronograph are they going to arrest you with ? I do got to guess and assume that these manufacturers pull one in ten thousand units off the assembly line and check it with somthing somehow ... Then what that somthing being checked with?

 

[Raider03]

This video provides a detailed discussion of the UK 12fpe limit. No twists and turns to try and obscure the topics importance. The presenter said the UK uses calibrated scan AR chronos. If you won't accepted those without a Tolkenish family tree going back to the most accurate chrono in all of history, that's your problem.
(Nor should anyone consider it a valid argument)

 

[bchannell]

There isn't a definitive way to pinpoint chrono accuracy at home, that's for sure.

What is close enough for me are
1) I compare to another chrony or two and if it's consistent, I'm good.

2) I know within a WAG what velocity my tune will provide, so I can get in the ballpark.

3) I can then shoot different distances using the velocity plugged into a ballistics calculator and see if it jives.

 

[NateChrony]

Perfect timing this pops up again!

Got my yearly measurements/calibration done - with new designs, new circuits, and new software.
Absolutely bonkers accuracy & really happy with the results!
Physical dimensions of the sampled units were within 0.01mm (uncertainty of 0.003)... I still dont get why people dont like 3D printing

Now for the data....
3 Units each received 300 sample shots (electronically triggered) all at 1,000fps

• Unit1:
  • Spread: 0.11fps
  • Difference from actual ~1,000fps measurement: -0.00087fps (avg)
• Unit2:
  • Spread: 0.09fps
  • Difference from actual ~1,000fps measurement: 0.00127fps (avg)
• Unit3:
  • Spread: 0.11fps
  • Difference from actual ~1,000fps measurement: -0.00099fps (avg)

Mounting the units back to back - we saw a difference of 0.34fps between the units, so we'll average that down to ~0.1fps & re-test.
These are different dimensions to the regular NateChronys - so expect the shot-shot resolution of a NateChrony to be around 0.25fps @ 1,000fps & within the usual 1fps @1,000fps of actual speed.

That's how I know my Chronographs are accurate, I put about 3 days of work in to make sure.

 

[Airgun-Revisions]

lol, this post sure did get a lot of feedback.

 

[cavedweller]

To the Brits it does. If your rifle shoots 12.01 fpe, you will go to jail.

 

[cavedweller]

Perfect timing this pops up again!

Got my yearly measurements/calibration done - with new designs, new circuits, and new software.
Absolutely bonkers accuracy & really happy with the results!
Physical dimensions of the sampled units were within 0.01mm (uncertainty of 0.003)... I still dont get why people dont like 3D printing

Now for the data....
3 Units each received 300 sample shots (electronically triggered) all at 1,000fps

• Unit1:
  • Spread: 0.11fps
  • Difference from actual ~1,000fps measurement: -0.00087fps (avg)
• Unit2:
  • Spread: 0.09fps
  • Difference from actual ~1,000fps measurement: 0.00127fps (avg)
• Unit3:
  • Spread: 0.11fps
  • Difference from actual ~1,000fps measurement: -0.00099fps (avg)

Mounting the units back to back - we saw a difference of 0.34fps between the units, so we'll average that down to ~0.1fps & re-test.
These are different dimensions to the regular NateChronys - so expect the shot-shot resolution of a NateChrony to be around 0.25fps @ 1,000fps & within the usual 1fps @1,000fps of actual speed.

That's how I know my Chronographs are accurate, I put about 3 days of work in to make sure.

Geeez Louise that’s serious work!