Does any know the G7 Form Factor of the (.30 cal) 230gr. Atips?

[Ballisticboy]

It’s important to note that the form factor is no less tied to a standard drag function than BC is. It’s just a fudge factor to make the math look nice.

I personally think we tend overstate the importance of custom drag curves, but sure, if they can be had (and are reliable), then by all means, we should use them. I wouldn’t lose sleep over it.

I cannot agree with this, the form factor is directly linked to the reference drag law. If you have a G7 and a G1 BC for the same bullet the form factors for each BC will be completely different depending on the drag law used. If you use the form factor to try to get the bullet drag curve you will also end up with two different drag curves based on their G7 and G1 form factors for the same bullet. While the predicted impact points may not be very different for the G7 or G1 drag laws the final velocities and times of flight will differ. They cannot both be right and in all probability neither is right, hence the desire for a purpose drag curve.
For much rifle shooting it does not make much difference which BC, form factor or drag curve you use for a particular bullet design but, as ranges increase, then it will become more important if reliable predictions are wanted.

 

[dcali]

I cannot agree with this, the form factor is directly linked to the reference drag law. If you have a G7 and a G1 BC for the same bullet the form factors for each BC will be completely different depending on the drag law used. If you use the form factor to try to get the bullet drag curve you will also end up with two different drag curves based on their G7 and G1 form factors for the same bullet. While the predicted impact points may not be very different for the G7 or G1 drag laws the final velocities and times of flight will differ. They cannot both be right and in all probability neither is right, hence the desire for a purpose drag curve.
For much rifle shooting it does not make much difference which BC, form factor or drag curve you use for a particular bullet design but, as ranges increase, then it will become more important if reliable predictions are wanted.

My wording was clumsy. I agree with you completely.