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Old 28th May 2014, 06:34 PM
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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
Posts: 2,335

Originally Posted by Ceathreamhnan View Post
Chairgun says there's no change in POI as far as I can see. It was the bit about the difference being so small you wouldn't notice that differs from my experience. I had a nice test card with 50 shots at 45y in each of N/S/E/W directions in a flat field that showed this, can't find it now!
I'm not saying there's not something in your findings.. but.. when you have real world findings that differ from the ballistic calculations that have been tried, tested and accepted for hundreds of years you've got to question if perhaps there was another factor or two that might have crept into your testing that you didn't realise?

Here's a couple of for instances....

How sure are you that the wind was parallel to the ground? Is there the slightest chance that the wind could have had a downward vertical component to it too?

How sure are you that your rifle wasn't canted? I'm guessing you were using your HFT rig which probably didn't have a spirit level fitted. If you shoot with a spirit level you'll be surprised at how many times your head tells you that you're level when a quick glance at the level says otherwise, even when you're on apparently level ground.

Both of those things could also have caused the results you observed, there are other possible explanations too.

If you look at it from another perspective - suppose you got everything right in your tests and there was no vertical component and no cant. What's your explanation for why the POI was lower? If the explanation is that it's because the pellet needs to travel further and therefore drops more - the extra distance is fairly easy to calculate and as a result the extra time and drop can also be calculated - I actually did this last year when Ian Taylor said the same thing at a really windy shoot and the result was that the extra distance wouldn't account for any sort of noticeable drop in POI. So... if it's not the extra distance and there's no vertical component to the wind - what's the explanation?

Now personally, I have more than a sneaking suspicion that there's more to the ballistic calculations with regard to airgun pellets, but in the absence of a controlled environment and lots of testing, I'm reluctant to try to come up with a theory to counter the accepted exterior ballistic calculations.

All that's an aside though - I can only code the game up with a calculation to give me an answer and the only calculations I've got are the ones from Chairgun, so I don't have a lot of choice. For the purposes of the game and what it's trying to emulate, it doesn't really matter too much. Interesting though.
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