Thread: Chrono Testing
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Old 14th December 2010, 09:47 PM
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rich rich is offline
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Join Date: Nov 2008
Location: Shebbear, N Devon
Posts: 1,643

When you set your own gun up, you use your own chrono. It doesn't matter whether you choose 780 or 760 or 500 for that matter, if the chrono on the comp site does not give the same reading as your own, subject to an agreed tolerance, then all your careful preparation work is like blowing in the wind.

A domestic SKAN has a stated tolerance of plus or minus 1 percent of the velocity reading. Note I said velocity reading because 1 percent on velocity is 2 percent on power as it's a square law function.

So when the BFTA chrono says 795 Oh that means you're OK, actually it could be anywhere from 795 minus 1 percent to 795 plus 1 percent, say 787 to 803. Whoops 803 that means I might be holding a section 1, aaargh I must go and fall on my sword etc.

The BFTA need to set a realistic limit bearing in mind the potential inaccuracy of the process in field conditions and the intrinsic variability and tolerances of the instrument.

There's been two pages on here since I replied to Holly's post; when I asked the BFTA for a proper discussion about the subject I got told, oh no not chronos again. Whenever we have that on the agenda the meetings go on for ever and ever, so we don't talk about the subject now. Well, the reason why the meetings go on and on is because there are so many unresolved issues, and refusing to debate them does nothing to reduce their number. If I don't look then perhaps they are not there...
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