Accuracy of Ballistic Programs

[idig4au]

Here is a question for the more experience long range shooters.

How do you find the accuracy of ballistics programs (JBM, Nightforce, etc) that calculate the bullet trajectory and corresponding bullet drops verses actual bullet drops measured at the range? Do you find the theoretical trajectory calculations in terms of bullet drops accurate or significantly off from reality? If there is a variance, then how significant and what order of magnitude? In terms of range, I'm talking about less than 700 yards.


Thanks for the input.

 

[Sam Millard]

As long as you start with an accurate muzzle velocity and a bullet with a BC that matches the published one, BulletFlight or Exbal should be spot on for you. They have both been on for me with 7 rifles...

 

[Broz]

Not to long ago I and another avid long range hunter took a rifle right off the bench and documented all the input data into several programs. Then we checked the rifles zero and inputted that. Then went to my personal range. We fired 2 shots from 800, 1200, 1600 and 1773 yards. Two shots to indicate a cold bore shot and a follow up shot. The next day we returned and did the test all over again, 2 shots from 800, 1200, 1600 and 1773. A total of 16 shots fired with the data entered right off the bench. Every point of impact for all 16 shots was inside 1/2 moa of point of aim. That means not one shot, even the ones fired from just over a mile were more than 9" from point of aim. This included wind calls and windage adjustments as well as elevation adjustments. So in a hunting scenario it would be 16 dead elk out to just over a mile with 16 shots fired.

All the apps we tested were pretty much in agreement with only small discrepancies. I used Applied Ballistics app on my droid phone utilizing their custom drag model for the bullet used. Other apps we tested were Cold Bore 1.0, Shooter, Bullet flight and a couple others.

Good input data will yield good shot solution data. Or an easier way to say it is, Garbage in, Garbage out.

Set them up and dial them in, with a decent rifle and ammo, and 700 yards is not a hard shot with due practice.

Jeff

 

[idig4au]

Thanks for the real world perspectives on this, much appreciated !