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Old 22nd April 2016, 10:50 AM
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Brian.Samson Brian.Samson is offline
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Join Date: Jun 2009
Member of: Pontefract, Doncaster Airgun Range
Location: Doncaster
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Originally Posted by Tench View Post
I agree the number is meaningless but an increase is an increase and brings benefits.
It's meaningless as a number quoted by a manufacturer when used as a comparison, but if you're doing tests of your own and you know that other variables haven't changed, or at least have some idea about how much they've changed then you can look at an increase as a positive thing.

What you can't do is see a quoted figure of 0.030 for a pellet and conclude that you're getting a better pellet than one quoted as 0.023, because you have no idea what the other variables are - most importantly being the drag profile used to calculate those figures.

As in the example I gave above - given the same MV and the same downrange velocity - I can get a BC of either 0.029 or 0.025 depending on which drag profile I use in the calculation (and those are just 2 profiles in CG).

There's nothing saying that the GA profile is correct for all shapes of pellet or all twist rates etc - it was only a profile made up by the author of CG.
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