Shooting the breeze Air Arms, World Class Air Rifles sponsors the British Field Target Association  
Go Back   Shooting the breeze > The Chat > Hunter / Field Target

Hunter / Field Target Anything metal target related...

Reply
 
Thread Tools Display Modes
  #131  
Old 28th May 2014, 04:01 PM
RobF's Avatar
RobF RobF is offline
My Empire of Dirt
 
Join Date: Mar 2010
Member of: Southampton Buccaneers, Parkstone, South Dorset
Location: Poole, Dorset
Posts: 10,641
Default

How would that work, the more luck the less chance?
__________________
BFTA/NSRA County Coach
CSFTA Chairman/BFTA Rep
Reply With Quote
  #132  
Old 28th May 2014, 04:32 PM
Brian.Samson's Avatar
Brian.Samson Brian.Samson is offline
Allowed in Sales
 
Join Date: Jun 2009
Member of: Pontefract, Doncaster Airgun Range
Location: Doncaster
Posts: 2,730
Default

Quote:
Originally Posted by RobF View Post
How would that work, the more luck the less chance?
Yeah that's what I was thinking, at the moment the game gives you little chance of making a splitter. You'd also be able to see if you made 40 perfect shots or whether luck played a big part
Reply With Quote
  #133  
Old 28th May 2014, 05:42 PM
Ceathreamhnan's Avatar
Ceathreamhnan Ceathreamhnan is offline
WHFTA Champion 2013
 
Join Date: Nov 2011
Member of: Dunfermline
Location: Stirling
Posts: 698
Default

Quote:
Originally Posted by Brian.Samson View Post
I haven't tried it, but have you checked Chairgun to see whether it says you'll get a lower poi in a strong cross wind?
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!
__________________
It's the Indian not the Arrow
Reply With Quote
  #134  
Old 28th May 2014, 06:34 PM
Brian.Samson's Avatar
Brian.Samson Brian.Samson is offline
Allowed in Sales
 
Join Date: Jun 2009
Member of: Pontefract, Doncaster Airgun Range
Location: Doncaster
Posts: 2,730
Default

Quote:
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.
Reply With Quote
  #135  
Old 28th May 2014, 08:05 PM
herx77 herx77 is offline
Senior Member
 
Join Date: Dec 2008
Member of: Lea Valley Air Gun Club
Location: The Bodyboarding capitol of Hertfordshire.
Posts: 403
Default

Quote:
Originally Posted by Brian.Samson View Post
Ah no.. there's no holdover or under on this - it's testing your ability to get the wind right so you're shooting with a gun thats zeroed for the target distance on every shot. If I'm bored again and I have some spare time, I might write an HFT version where you also have to get your holdover right as well.
Nice one Brian,I would like to be able to give hold over etc but challenging just the same ;only got 28 so far!
Going to be a long,long night, b****r! .
HERX77 .
__________________
Fighter against the 'Dark Arts'
Dark keeps moving in on the day.
Steadily going downhill faster!
Reply With Quote
  #136  
Old 28th May 2014, 08:11 PM
herx77 herx77 is offline
Senior Member
 
Join Date: Dec 2008
Member of: Lea Valley Air Gun Club
Location: The Bodyboarding capitol of Hertfordshire.
Posts: 403
Default

Quote:
Originally Posted by Brian.Samson View Post
That option's only available in the HFT version
Make it an 'extra large' option then Brian! .
HERX77 .
__________________
Fighter against the 'Dark Arts'
Dark keeps moving in on the day.
Steadily going downhill faster!
Reply With Quote
  #137  
Old 28th May 2014, 08:36 PM
Brian.Samson's Avatar
Brian.Samson Brian.Samson is offline
Allowed in Sales
 
Join Date: Jun 2009
Member of: Pontefract, Doncaster Airgun Range
Location: Doncaster
Posts: 2,730
Default

Quote:
Originally Posted by herx77 View Post
Nice one Brian,I would like to be able to give hold over etc but challenging just the same ;only got 28 so far!
Going to be a long,long night, b****r! .
HERX77 .
I was having a think about how I could do this.. my current thinking is that from the ballistic info you enter I could automatically calculate a holdover chart for you.. then I'd probably need to have another input screen so you could tweak the holdovers to better match your own (in case the Chairgun holdovers don't match up perfectly).

Then to emulate a ranging error, I could get the game to randomly lie about the range in the top left of the screen. So for example, you tell it your ranging error is 2 yards and it could potentially lie about a 45 yard target telling you it's actually 43 (to emulate you getting the range wrong).

Dunno how I'd emulate parallax error and scope blur though

btw, although the apparent magnification of the scope is 16x mag - the mildot rets are set to be true mildots, so it should work out pretty well for HFTer's with true mildot scopes even as it is.
Reply With Quote
  #138  
Old 28th May 2014, 08:59 PM
Ceathreamhnan's Avatar
Ceathreamhnan Ceathreamhnan is offline
WHFTA Champion 2013
 
Join Date: Nov 2011
Member of: Dunfermline
Location: Stirling
Posts: 698
Default

Quote:
Originally Posted by Brian.Samson View Post
How sure are you that the wind was parallel to the ground?
Like I say, on a field (actually a dispersal area on a WWII airfield) on a flat farm.

Quote:
How sure are you that your rifle wasn't canted?
I'm shooting at a card with a grid drawn on it parallel to the ground with a mildot ret lined up with the grid

I agree with your assertion that the extra distance wouldn't make any odds, much like the sin theta/theta = 1 thing for small angles. But I suspect, like you say, for diabolo pellets BC theory needs an extra complication.
I originally did the test to see for myself whether the suggested idea of rifling going in one direction would make a difference in POI for left v right wind, which I couldn't see. But both groups for left and right, with varying amounts of wind (it was very windy, around 2 mildots @10x at 45y), resulted in a lower average POI than you would get for the same setup with no wind.
__________________
It's the Indian not the Arrow
Reply With Quote
  #139  
Old 28th May 2014, 08:59 PM
herx77 herx77 is offline
Senior Member
 
Join Date: Dec 2008
Member of: Lea Valley Air Gun Club
Location: The Bodyboarding capitol of Hertfordshire.
Posts: 403
Default

Quote:
Originally Posted by Brian.Samson View Post
I was having a think about how I could do this.. my current thinking is that from the ballistic info you enter I could automatically calculate a holdover chart for you.. then I'd probably need to have another input screen so you could tweak the holdovers to better match your own (in case the Chairgun holdovers don't match up perfectly).

Then to emulate a ranging error, I could get the game to randomly lie about the range in the top left of the screen. So for example, you tell it your ranging error is 2 yards and it could potentially lie about a 45 yard target telling you it's actually 43 (to emulate you getting the range wrong).

Dunno how I'd emulate parallax error and scope blur though

btw, although the apparent magnification of the scope is 16x mag - the mildot rets are set to be true mildots, so it should work out pretty well for HFTer's with true mildot scopes even as it is.
Don't care about 'real mil dots' as I use parallexing which is not optional! ie Real at 10x on my Bushnell,but I use 8.5x, which isn't. Just give me division marks on graticle and I will do the rest,, (sometimes).
Whats your take on the NJR100 with olympus trigger.
HERX77 .
__________________
Fighter against the 'Dark Arts'
Dark keeps moving in on the day.
Steadily going downhill faster!

Last edited by herx77; 28th May 2014 at 09:02 PM.
Reply With Quote
  #140  
Old 28th May 2014, 09:26 PM
Brian.Samson's Avatar
Brian.Samson Brian.Samson is offline
Allowed in Sales
 
Join Date: Jun 2009
Member of: Pontefract, Doncaster Airgun Range
Location: Doncaster
Posts: 2,730
Default

Quote:
Originally Posted by Ceathreamhnan View Post
Like I say, on a field (actually a dispersal area on a WWII airfield) on a flat farm.


I'm shooting at a card with a grid drawn on it parallel to the ground with a mildot ret lined up with the grid

I agree with your assertion that the extra distance wouldn't make any odds, much like the sin theta/theta = 1 thing for small angles. But I suspect, like you say, for diabolo pellets BC theory needs an extra complication.
I originally did the test to see for myself whether the suggested idea of rifling going in one direction would make a difference in POI for left v right wind, which I couldn't see. But both groups for left and right, with varying amounts of wind (it was very windy, around 2 mildots @10x at 45y), resulted in a lower average POI than you would get for the same setup with no wind.
It's a quandary that's for sure.. I wasn't really asking questions that needed to be answered, just coming up with things that people don't always consider when they do tests like this.

So for example - a flat field doesn't necessarily rule out a vertical component to the wind, a grid parallel to the ground doesn't rule out that the ground isn't level. If you're moving the target N,E,S,W - is there a chance that when you move it to a different direction it's 44 yards and when it goes to another it's 46 etc. again, not questions that I'm firing at you, just pointing out the dangers of drawing conclusions from tests that aren't controlled.

Look at it like this - if you got everything perfect and it was a fully controlled test - what possible reason is there to explain the result? If it's not the extra distance (I'm pretty sure it can't be that, because that can be calculated and it's very small) then what is it?

The only explanation I can think of is that something's amiss with the testing environment? Another possibility is precession due to barrel/twist rate and rifling marks perhaps??

What we need is a University to get a grant to study airgun pellet ballistics - if they can get grants to study the sogginess of cornflakes I'm sure they can get a grant to study something useful
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Super secret Gahtering song 2013 scutter UKAHFT Official Forum 13 9th December 2012 05:29 PM
Shooting in Wind Sparky Tips, tricks and tutorials 52 28th February 2011 05:08 PM
READING THE WIND or Shooting In The Breeze PeteM Hunter / Field Target 13 13th October 2010 08:29 PM
millride wind chink Hunter / Field Target 18 21st August 2009 10:37 PM
Reading wind ? FUBAR Hunter / Field Target 32 23rd July 2009 08:05 PM


All times are GMT. The time now is 06:41 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
shooting-the-breeze.com Skin design and concept by Attitude