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Old 3rd October 2013, 10:20 AM
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kieran turner kieran turner is offline
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Join Date: Apr 2009
Location: Scunthorpe, N.Lincs
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Originally Posted by Brian.Samson View Post
I'll come up with some answers for you at lunchtime K.. but just quickly, we don't agree with the first bit.. 40fps downrange can (we think) in theory still hit the same POI. But.. it would depend on the velocity it started at (which we don't know)

Secondly, the lapua example.. The smaller the variation in MV as a percentage of the total velocity will have less effect.

So, for example, if you're getting a 50fps variation against a velocity of say 780 fps, the difference in POI will be much greater than if you're getting a 50fps variation against a velocity of 2000 fps. How much difference it makes would need to be calculated, but it might not be huge. Dunno?..

Anyhoo.. I'll see if I can come up with a sensible answer for the 40fps hitting the same level later on. If I had to put money on it though, I think the answer will be - either Si's reg is seriously foooked or he pulled the shot, or the chrono reading was wrong, or maybe there was some weird wind effect. Oh, or ballistics is wrong
I was just sat thinking something similar with regards to percentage of total variation, just for the record factory stated velocity was something obscure like 3010fps, but in a Uk climate I think it was around 2800fps.

I am very tempted to acquire a second chronograph and go indoors and try and get some more data for the air rifle debate(wouldn't fancy indoors with .338). If memory serves me right though Brian cast your mind back to yesterday year (que relevant music) when we used to shoot at Anston didn't your Steyr have a variation of something like 25fps yet was still insanely accurate?
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