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Ballistics isn't the math the math?

 
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  #8  
Old 02-13-2012, 09:22 PM
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Re: Ballistics isn't the math the math?

Thanks all, evidently there is a lot more going on in the math.
I'll just shoot the distances and get the numbers in reality with the ballistic profiles as my starting point.
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  #9  
Old 02-13-2012, 09:41 PM
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Re: Ballistics isn't the math the math?

One of the items I could see being a difference is the "sample rate". What it means is that you will have to pick how often (at what interval) the change in velocity (and drop and drift) is calculated. If you do this at different rates then you will have different answers.

Easiest way to explain it probably is taking interest calculation as an example. If I loan someone money, would it be best for me to add up interest to the principal every day, every month or just once a year? Every day of course because next day I would be getting interest on the interest. Same applies to ballistic calculation as well.

If one knows a little about programming, here is an open source ballistic program that you can download and play with the code: http://sourceforge.net/projects/balcomp/
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  #10  
Old 02-13-2012, 10:14 PM
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Re: Ballistics isn't the math the math?

Just to reiterate what everyone has said it is most likely these reasons:

Between "your" drop chart and the programs is the difference introduced by the unique nature of your rifle.

Between the different programs, it is undoubtedly a combination of sample rate and resolution (significant figures) in the calculations. Just like the impact of a bullet @ 100m and @1000m (without adjusting the scope), there is a BIG difference between rounding @ the tenths and rounding at the thousandths.

I personally would either forget about it, or call the software developers, figure out who's using the highest resolution+sample rate, and discontinue use of the others.
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Old 02-13-2012, 10:50 PM
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Re: Ballistics isn't the math the math?

FWIW....guys I've been shooting LR a helluva long time.....longer than I care to recall matter of fact. First beginnings was with an 03 Springfield and I've fired many rifles and calibers over 60 years of shooting....all the way back to 1600 yards...or more! AND...my conclusion was over a long period of time that these so-called ballistic charts are good gizmos to con $$$$$ out of people. Now...some will of course rebut that statement but be that as it may....I'll still cling to my own experience and as stated conclusion! Shoot your rifles with the best load that you can get it to develop....record all data related to weather conditions and then use that data to help you in future shootings! Temperature makes a helluva difference I can tell you that from one day to the next and if not taken into consideration...well...you won't be close to what you're gonna want to hit! Once you've found a load combination that works...don't get caught in the trap of constantly chasing a magic new bullet because there are NO MAGIC BULLETS....just raw physics and well established science!
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  #12  
Old 02-13-2012, 11:19 PM
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Re: Ballistics isn't the math the math?

Quote:
Originally Posted by Swampy79 View Post
there is a BIG difference between rounding @ the tenths and rounding at the thousandths.
There should be no rounding during calculations so that should not be an issue. Calculating trajectory is actually a fairly simple routine, to be honest with. Even with the sampling rate there should not be significant differences unless one program uses very coarse interval.

For example if I calculate drop using 1ms interval, I get 538.33" of drop and if I switch to 0.1ms I get 537.94". Not a very significant change. This actually leads me to believe there are possible software bugs in the program. As always, it is best if you write your own...
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  #13  
Old 02-14-2012, 04:35 PM
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Re: Ballistics isn't the math the math?

Quote:
Originally Posted by Sharpsman View Post
FWIW....guys I've been shooting LR a helluva long time.....longer than I care to recall matter of fact. First beginnings was with an 03 Springfield and I've fired many rifles and calibers over 60 years of shooting....all the way back to 1600 yards...or more! AND...my conclusion was over a long period of time that these so-called ballistic charts are good gizmos to con $$$$$ out of people. Now...some will of course rebut that statement but be that as it may....I'll still cling to my own experience and as stated conclusion! Shoot your rifles with the best load that you can get it to develop....record all data related to weather conditions and then use that data to help you in future shootings! Temperature makes a helluva difference I can tell you that from one day to the next and if not taken into consideration...well...you won't be close to what you're gonna want to hit! Once you've found a load combination that works...don't get caught in the trap of constantly chasing a magic new bullet because there are NO MAGIC BULLETS....just raw physics and well established science!
True.

The latest software is great for plugging in basic parameters, e.g. BC and MV, to get on paper at long distance so that you can confirm your drops.

They're also good for checking the anticipated correction for different conditions such as altitude, wind, or in-between/unknown distances that you haven't shot.

It's always best to verify actual dope in the field.

The ELR guys have to really pay attention to fine details as they get out past 1200 yds or so. ...unless you're just trying to walk it in.

Given the cost of ammo and barrel life, I think good software is well worth the $$.

-- richard
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