Commercial optical chronographs read arrow speed with an error of a couple of per cent

The summary today

There is a single test, from 2011, and it was not designed to judge chronographs: a research group validating an electronic arrow point with an accelerometer used the ballistic chronograph at NIST, the US standards institute, as its reference. Over four shots from a machine with a 60.6 lb compound the arrow leaves the bow at 82.575 metres per second according to the reference; three commercial chronographs on the same line read 81 or 81.33 on average, between 1.5 and 1.9 per cent low, while the electronic point stays within 0.59 per cent. Two details matter to anyone who uses one: all three instruments were off in the same direction, reading low, and they gave the speed to the whole metre per second, a resolution that on its own amounts to more than one per cent at these speeds. The authors themselves write that the stated accuracy of such devices is usually around 0.5 per cent and depends heavily on the light. The limit is the size of the test: four shots, one bow, one arrow and three instruments whose models the paper does not name.

Also phrased as: "chronograph accuracy"; "arrow chronograph error"; "measuring arrow speed"; "how accurate is an arrow chronograph"

Evidence

• 2011
  For Equipment tests Published later

  Validation of an electronic arrow point on the NIST ballistic range: an Elite Hunter compound at 60.6 lb and 29 inch draw, Easton ST Epic arrows of 24.75 grams shot from a machine at 13.94 metres. The reference chronograph reads a mean of 82.575 metres per second over four shots (standard deviation 0.45); three commercial chronographs read means of 81, 81 and 81.33, between 1.5 and 1.9 per cent low and always to the whole metre per second, while the electronic point gives 82.09 with a standard deviation of 0.07, within 0.59 per cent.

  A miniaturised arrow ballistic measurement system · John Barton, Jan Vcelak, Javier Torres-Sanchez, Brendan O'Flynn, Cian O'Mathuna, Robert V. Donahoe

Status history

1. 2011 Reported The only measurement arrives. A group validating an arrow point with an accelerometer compares three commercial chronographs with the NIST reference ballistic chronograph over four machine shots with a compound: the three read between 1.5 and 1.9 per cent low, all in the same direction and to the whole metre per second, while the point stays within 0.59 per cent. It is a single small test with instruments whose models are unknown: reported.

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