Range Report HELP Needed with Ballistic Program Differences

[crossgun]

Ok so here is my problem. I am running iSnipe, BulletFlight and Ballistic FTE on my iPod touch. In both my 308 and 260 my dope is really close to iSnipe (with in 0.25MOA) but as much as 2MOA off at longer ranges (1000) with the others and BulletFlight being the worst.

Seeing as there are so many variables and to me speed being the one that is more than likely the largest should I play with the velocity to see if it will get a little closer? I am using G7s from Litz. Have to say that I hate the whole chronograph thing seeing there is really no way to know for sure. None of them are calibrated to a "standard" so to me it would seem that FPS is more than likely the problem?

iSnipe does not have a HUD which is a feature I really like in the others.

What should I adjust?

 

[The Mechanic]

Re: HELP Needed with Ballistic Program Differences

Last thing you should adjust is velocity. You need to shoot at various distances and at the longest range you can find and adjust to fit as best as possible to your real life results.

 

[Travelor]

Re: HELP Needed with Ballistic Program Differences

I have found NO computer ballistics program that will match the range results of my guns. They get close, but no spot on.

Strangely enough, the JBM ballistics program on my iPhone that allows for real time weather data works better that the desk top PC programs I have. As a FYI, QuickLoad is a very good estimator of velocities you can expect if you input all the variables correctly.

 

[MALLARD]

Re: HELP Needed with Ballistic Program Differences

my ballistic programs put my pretty close inside 700y. I dont think JBM corrects for spindrift though.Perhaps the programs your using isnt accounting for air resistance and thats why your drops off. or maybe you input the wrong number, could be allot of things, bc or bullet stability maybe be unaccounted for or off.

 

[Rafael]

Re: HELP Needed with Ballistic Program Differences

What should you adjust? You.
Why spend time trying to get three programs to agree when you seem to be overwhelmed by all of the data?

Pick one program. Pick it for the features you like...not how lucky you got with how closely it matches your dope. Work towards collecting correct data for all variables. Go out and shoot at various differences.

If you cannot get the program to agree with the shooting results...come back here and post all variables and results and I am sure the problem can be resolved.

When you have a good understanding of the one program and all of the variables....then you can take a look at the others and do a comparison.....if you are so inclined.

 

[ReaperDriver]

Re: HELP Needed with Ballistic Program Differences

I have both Bulletflight and Ballistic and struggled with getting them to match my actual dope. However, once I started using station pressure instead of corrected sea level pressure in the calcs - all of a sudden my data started coming in line with actual dope. Just a thought.....

 

[gafferq2xl]

Re: HELP Needed with Ballistic Program Differences

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">However, once I started using station pressure instead of corrected sea level pressure in the calcs - all of a sudden my data started coming in line with actual dope. Just a thought..... </div></div>

+1 on that

 

[Lindy]

Re: HELP Needed with Ballistic Program Differences

A couple of things which might be worth reading with respect to this issue:

Barometric Pressure and Ballistic Software

Sources of Ballistic Program Inaccuracies

 

[crossgun]

Re: HELP Needed with Ballistic Program Differences

Lindy

Thanks for the great info. Now my head really hurts. No reason for me to over think it. It appears that actual DOPE is the ticket. Tweaking the BC of the bullet did get me a pretty good match. It was closer than what I got by adjusting the velocity.

 

[azimutha]

Re: HELP Needed with Ballistic Program Differences

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I have both Bulletflight and Ballistic and struggled with getting them to match my actual dope. However, once I started using station pressure instead of corrected sea level pressure in the calcs - all of a sudden my data started coming in line with actual dope. Just a thought..... </div></div>

When you were using corrected pressure did you enter the altitude? I've read that using station pressure is better (and I do if I bring my GPS along with me just to get an up-to-date reading) but haven't seen much difference in the results. For example, if I use a corrected pressure of 29.92 and input an altitude of 6000' I get a drop at 1000 yards of 346.5" vs. using 23.99 and 0' which yields 346.6" (using JBM or Ballistic/JBM engine)

 

[ReaperDriver]

Re: HELP Needed with Ballistic Program Differences

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: azimutha</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ReaperDriver</div><div class="ubbcode-body">I have both Bulletflight and Ballistic and struggled with getting them to match my actual dope. However, once I started using station pressure instead of corrected sea level pressure in the calcs - all of a sudden my data started coming in line with actual dope. Just a thought..... </div></div>

When you were using corrected pressure did you enter the altitude? I've read that using station pressure is better (and I do if I bring my GPS along with me just to get an up-to-date reading) but haven't seen much difference in the results. For example, if I use a corrected pressure of 29.92 and input an altitude of 6000' I get a drop at 1000 yards of 346.5" vs. using 23.99 and 0' which yields 346.6" (using JBM or Ballistic/JBM engine) </div></div>

Yes, I was using alt and corrected pressure by trying to find an altimeter setting somewhere close to my location. The problem is unless you're standing on an airfield when you shoot - you're more than likely going to have some errors as you get further away in both distance and elevation from whereever the sea level corrected altimeter setting is from.

I now use station pressure instead. Using station pressure from a kestrel or some other source you have with you (I have a Suunto watch that gives me station pressure) will give you THE most accurate pressure reading for your current conditions.

 

[azimutha]

Re: HELP Needed with Ballistic Program Differences

Got it. Sounds like we're talking about two different factors. I was thinking just the difference between using corrected pressure + altitude vs. station pressure (no altitude) under the exact same conditions, i.e. no change in position or altitude.

Just to clarify then:

If you have access to current pressure, by all means use it. AFAIK, there is no difference between using corrected pressure (as long as you input the altitude) and using station pressure as far as the ballistics calculator is concerned. However, if you just use station pressure, you can leave altitude set at zero and not have to take the time to ensure that it has been entered...and entered correctly.