Ballistic calculator

[BallisticsGuy]

If the output is wrong by more than 1-2 clicks, the inputs are wrong. Simple as that. If you want help fixing your inputs, PM me. I publish a ballistics calculator so I might know one or two things about using them. User error is 100% of the causes of output errors.

 

[ARlife4me]

Making sure ALL info is in the same scale (imperial vs metric/inches vs mm/ yards vs meters) and so forth. I've had app cross issues before on comparing/cross checking multiple. Making sure you're using imperial on moa and metric on mils.

 

[Mr1Fixit]

I'd encourage you to remember that all the computers do is model your performance. If you have a load that shoots with a consistent velocity (small velocity SD), the ballistics should be repeatable as evidenced by the groups you shoot at distance. My suggestion is calibrate your model - make sure your inputs for everything you control and measure reliably are as good as you can make them. Then calibrate the trajectory model out to your max range by adjusting either velocity or ballistics coefficient (they have similar effect on the calculation, if I understand it correctly). I have done that for a 7mm WSM of mine and found it good past 1200 yards on targets after changing the velocity input from what I had chronographed to what matched the observed trajectory. I think what you see in the real world is the best basis for your model.

 

[SSgt G Cody]

Hmmm! If I understand you, 300 yds called for a 1.8 moa correction, which is 5.5 inches! Are you actually hitting 8 in. low? I have never seen a calculator off more than maybe .2 moa, providing all correct info was entered! Also, re-check your zero!

 

[DDWing]

2.75 is that right for the scope height

Correct.

I'd encourage you to remember that all the computers do is model your performance. If you have a load that shoots with a consistent velocity (small velocity SD), the ballistics should be repeatable as evidenced by the groups you shoot at distance. My suggestion is calibrate your model - make sure your inputs for everything you control and measure reliably are as good as you can make them. Then calibrate the trajectory model out to your max range by adjusting either velocity or ballistics coefficient (they have similar effect on the calculation, if I understand it correctly). I have done that for a 7mm WSM of mine and found it good past 1200 yards on targets after changing the velocity input from what I had chronographed to what matched the observed trajectory. I think what you see in the real world is the best basis for your model.

This load has a SD of 1, and an ES of 3, on a 5 shot group. I have tried changing MV and BC, but still can't get anything to line up correctly. I just finished shooting this evening out to 500 yrds. At 500 strelok said 6.71 and was almost 14" low. These are my final shots at 3,4, and 5 hundred. Bottom center was 300. I adjust my dope card for the 2" difference. Left is 400, and right is 500. This is adjusting for the extreme difference in ballistics on strelok.

I'd encourage you to remember that all the computers do is model your performance. If you have a load that shoots with a consistent velocity (small velocity SD), the ballistics should be repeatable as evidenced by the groups you shoot at distance. My suggestion is calibrate your model - make sure your inputs for everything you control and measure reliably are as good as you can make them. Then calibrate the trajectory model out to your max range by adjusting either velocity or ballistics coefficient (they have similar effect on the calculation, if I understand it correctly). I have done that for a 7mm WSM of mine and found it good past 1200 yards on targets after changing the velocity input from what I had chronographed to what matched the observed trajectory. I think what you see in the real world is the best basis for your model.

I'd encourage you to remember that all the computers do is model your performance. If you have a load that shoots with a consistent velocity (small velocity SD), the ballistics should be repeatable as evidenced by the groups you shoot at distance. My suggestion is calibrate your model - make sure your inputs for everything you control and measure reliably are as good as you can make them. Then calibrate the trajectory model out to your max range by adjusting either velocity or ballistics coefficient (they have similar effect on the calculation, if I understand it correctly). I have done that for a 7mm WSM of mine and found it good past 1200 yards on targets after changing the velocity input from what I had chronographed to what matched the observed trajectory. I think what you see in the real world is the best basis for your model.

 

[DDWing]

Hmmm! If I understand you, 300 yds called for a 1.8 moa correction, which is 5.5 inches! Are you actually hitting 8 in. low? I have never seen a calculator off more than maybe .2 moa, providing all correct info was entered! Also, re-check your zero!

I have checked and rechecked everything. I'm at a total loss on what the problem might be.

 

[asd9055]

@DDWing we had 10 pages of comments...and I don't want to go trhough them again...
if you want me to attempt on the calculaters I have just post a summary of data again.
and how far is chrono from muzzle

 

[DDWing]

@DDWing we had 10 pages of comments...and I don't want to go trhough them again...
if you want me to attempt on the calculaters I have just post a summary of data again.
and how far is chrono from muzzle

Using the Caldwell, about 6 ft. My magneto speed attaches to the barrel. I normally use the magneto speed because the Caldwell is bad about giving errors when doing load development.

 

[asd9055]

do you have a summary of new data? zero @100, mv, then how olw it hit at distance

 

[xsn10s]

I have checked and rechecked everything. I'm at a total loss on what the problem might be.

I believe that when you imput scope height of 2.75 inches you need to be sure it's being input as inches instead of centimeters (cm).

 

[DDWing]

I believe that when you imput scope height of 2.75 inches you need to be sure it's being input as inches instead of centimeters (cm).

It is.

 

[asd9055]

It is.

if you make no adjustments on your scope, what is the drop you get in 300 or 500 yards

 

[Veteran]

Xns10s asked if you were using 2.75 centimeters as input on scope height instead of 2.75 inches. Metric and English units differences.....I never saw an answer, only that 2.75 was right?
possible confusion on units input?

 

[Veteran]

ok, I see the scope height got clarified as I was posting...