Kestrel/Hornady 5700 4DOF - axial form factor

[Paul1262]

If you select a bullet from the bullet library that indicates G1 G7 and 4DOF , and you select 4DOF, should the axial form factor number be 0 ?
Thanks

 

[Woodland_Wolf_M81]

Per the instructions I found on Hornady's website:

Axial Form Factor:
Allows the shooter to adjust the average Drag Coefficient (Cd) curve for each projectile listed in the calculator, higher or lower, to match his/her specific barrel, propellant, twist rate, rifling, muzzle brake, etc. (all these variables have an effect on the drag performance of a projectile).

1. Insert all other input information
2. Leave Axial Form Factor input at the standard (1.0)
3. Shoot your rifle, then measure the elevation deviation, as accurately as possible, from the trajectory solution given in the calculator to that of what was shot. NOTE: Shoot at the farthest distance you can without compromising the ability to get an accurate point of aim/point of impact results in order to measure deviation.
4. Adjust the Axial Form Factornumber either up to drop, or down to elevate the trajectory given in the calculator until it matches the trajectory you shot.
   • If impacts are HIGHER than the predicted trajectory, DECREASE the Axial Form Factor number until the predicted and actual trajectory match.
   • If impacts are LOWER than the predicted trajectory, INCREASE the Axial Form Factor number until the predicted and actual trajectory match.
5. Keep the Axial Form Factor number for the gun, bullet, and load you shot somewhere for safe keeping. This number is specific to that rifle and load and should be used to calculate accurate trajectory information anytime you use the Hornady 4DOF® Ballistic Calculator.

 

[Paul1262]

Per the instructions I found on Hornady's website:

Axial Form Factor:
Allows the shooter to adjust the average Drag Coefficient (Cd) curve for each projectile listed in the calculator, higher or lower, to match his/her specific barrel, propellant, twist rate, rifling, muzzle brake, etc. (all these variables have an effect on the drag performance of a projectile).

1. Insert all other input information
2. Leave Axial Form Factor input at the standard (1.0)
3. Shoot your rifle, then measure the elevation deviation, as accurately as possible, from the trajectory solution given in the calculator to that of what was shot. NOTE: Shoot at the farthest distance you can without compromising the ability to get an accurate point of aim/point of impact results in order to measure deviation.
4. Adjust the Axial Form Factornumber either up to drop, or down to elevate the trajectory given in the calculator until it matches the trajectory you shot.
   • If impacts are HIGHER than the predicted trajectory, DECREASE the Axial Form Factor number until the predicted and actual trajectory match.
   • If impacts are LOWER than the predicted trajectory, INCREASE the Axial Form Factor number until the predicted and actual trajectory match.
5. Keep the Axial Form Factor number for the gun, bullet, and load you shot somewhere for safe keeping. This number is specific to that rifle and load and should be used to calculate accurate trajectory information anytime you use the Hornady 4DOF® Ballistic Calculator.

Thanks I appreciate you putting this together. I wasn't sure if you did all of the above steps starting with the Axial Form Factor at 1.0 or 0.

 

[striped1]

I find with trying to true my .22, it takes a combination of muzzle velocity and AFF tweaking to true my 4DOF to actual.

 

[Paul1262]

I find with trying to true my .22, it takes a combination of muzzle velocity and AFF tweaking to true my 4DOF to actual.

Just curious at what distance(s) do you true your .22 at?

 

[Paul1262]

Just as a side note to Woodland and striped1. If you use the Kestrel link to enter your data, under Axial Form Factor is states "Leave blank if unknown". Thanks to both for your comments.

 

[striped1]

The range I have goes to 250. I have used the combo of AFF and muzzle velocity to true the kestral to the data I get in from the targets in 50 yard increments from 50 to 250. I have been able to use that data to get a solution to 285, but not any farther to see how far it stays trued.

I am using the Kestral but not the link.

 

[Paul1262]

The range I have goes to 250. I have used the combo of AFF and muzzle velocity to true the kestral to the data I get in from the targets in 50 yard increments from 50 to 250. I have been able to use that data to get a solution to 285, but not any farther to see how far it stays trued.

I am using the Kestral but not the link.

Thanks for the information.