Ballistic calculator vs real dope

[WKR]

Anyone have any major differences between what they punched in on a ballistic calculator and the actual results in the field with their handloads?
I started stretching out a load i developed for my 7MM rem mag and I'm a little perplexed. At 400 yards I had a difference of .5 moa between what the calculator said and my point of impact. Which is acceptable but then at 500 I needed to dial 8 moa to be on target when the ballistic app said only 6.5 moa.

So whats going on? I'm using a magneto speed to get the data used in My calculations. I was shooting into a 8-10 mph head wind but that shouldn't constitute a 1.5 moa drop.

 

[Rob5589]

Calculators get you in the ballpark.

 

[BBob]

You have input/inputs wrong in the app. Garbage in garbage out.

 

[Ucsdryder]

I’ve been told the hardest to calculate is bc. Lots of manufacturers fudge the number plus bc changes with speed. So you might need to play around with your calculator and increase/decrease bc to see if you can get the numbers to match with your true dope.

 

[BBob]

What scope are you using? Are you sure of what the elevation unit is? There are still scopes out there that use IPHY (inch per hundred yard) and not MOA. They are not the same. Some early March scopes used an older and not used much anymore MIL measurement (they have changed it in current scopes). It is not the same as most everyone else's current and modern MIL. My point is there are many errors possible in setting up the APP to get correct data out of it. It is also not uncommon at all to need to "True" your inputs to get correct data out. Search for ballistic APP truing and you find tons of info to read and learn. Lots of info on how to get a ballistic APP working correctly and trued over on Snipers Hide. There is no reason why you cannot get it setup correctly and get good data out of it if you figure out what needs to be fixed or trued.

 

[Wrench]

I use chronograph to get spreads down and ball park the velocity. I shoot to 600 and record drops for velocity dope. 800 out for bc validation.

 

[Wrench]

Great point on the scope....tall target test to reveal what your actual click values are. .25" might be .24 or 255.....that's where the rubber meets the road and everything has to be repeatable.

 

[willfrye027]

That’s a pretty significant difference. Are you positive you are perfectly zero at 100?

 

[Travis Bertrand]

something is wrong, What calculator are you using? You always will have to adjust FPS, and BC to true your calcs

 

[Rock-o]

I go the opposite direction. Field data -> calculator. "Try Dope"... "Weaponized Math". It works. No chronograph needed. Get all your calculator inputs correct and you're solid. Quick and easy.

 

[WKR]

I'm shooting a 169 gr bullet with a estimated G1 bc of .550 at an avg muzzle velocity of 3080 fps. I've tried inputting some different numbers in the calculator but it doesn't really coincide with my real world data.
Maybe I should just keep the same point of aim, walk it back and measure drops.
It just confuses me why the calculations are that far off

 

[WKR]

What scope are you using? Are you sure of what the elevation unit is? There are still scopes out there that use IPHY (inch per hundred yard) and not MOA. They are not the same. Some early March scopes used an older and not used much anymore MIL measurement (they have changed it in current scopes). It is not the same as most everyone else's current and modern MIL. My point is there are many errors possible in setting up the APP to get correct data out of it. It is also not uncommon at all to need to "True" your inputs to get correct data out. Search for ballistic APP truing and you find tons of info to read and learn. Lots of info on how to get a ballistic APP working correctly and trued over on Snipers Hide. There is no reason why you cannot get it setup correctly and get good data out of it if you figure out what needs to be fixed or trued.

Scope is a Zeiss v4. Its a true moa scope.

 

[WKR]

something is wrong, What calculator are you using? You always will have to adjust FPS, and BC to true your calcs

I've used shooterscalculator.com and hornadys

 

[Rob5589]

I'm shooting a 169 gr bullet with a estimated G1 bc of .550 at an avg muzzle velocity of 3080 fps. I've tried inputting some different numbers in the calculator but it doesn't really coincide with my real world data.
Maybe I should just keep the same point of aim, walk it back and measure drops.
It just confuses me why the calculations are that far off

"Estimated bc." Guessing you're using Hammers.

 

[Travis Bertrand]

I'm shooting a 169 gr bullet with a estimated G1 bc of .550 at an avg muzzle velocity of 3080 fps. I've tried inputting some different numbers in the calculator but it doesn't really coincide with my real world data.
Maybe I should just keep the same point of aim, walk it back and measure drops.
It just confuses me why the calculations are that far off

What bullet exactly?


Sent from my iPhone using Tapatalk

 

[Travis Bertrand]

Scope is a Zeiss v4. Its a true moa scope.

What he means is to verify your clicks. Specs say this but real life might be different.


Sent from my iPhone using Tapatalk

 

[WKR]

What bullet exactly?


Sent from my iPhone using Tapatalk

Hammer Hunter 169's

 

[WKR]

"Estimated bc." Guessing you're using Hammers.

Yup thats right, do you think there estimation can be that far off? To get 7.75 moa at 500 on the calculator I have to punch in a way lower bc

 

[Travis Bertrand]

With your rough data. This is what applied ballistics shows


Sent from my iPhone using Tapatalk

 

[WKR]

With your rough data. This is what applied ballistics shows


Sent from my iPhone using Tapatalk

That looks more accurate, I will try that app