Or does anyone know how to figure it with the available data? I was currious if it was close to .800...
Thank You.
Thank You.
You might spend a little time looking for that number yourself. It's not hard to find. BTW you have the G1 and G7 numbers backwards.
https://www.hornady.com/bullets/a-tip-match#!/
I think part of the problem is that you are asking about form factors where as the data on the Hornady site is BCs apparently causing some confusion. I could not see or find any information on form factors on the Hornady site. While the two are related they are not the same. The damoncali formula will give you the form factors from the stated BCs.
Based on the Hornady figure the form factor is about .837 for the G7 drag law.
A lower form factor isn’t generally going to result in the highest BC for a given bullet length. You have to balance weight, BC, and length in a sort of compromise. Low form factor bullets are light and skinny, which isn’t optimal for BC (again, given a bullet length).
I get: ((230/7000) / .308^2))/ .414 = .839 . Essentially as good as .837, .414 is the G7 BC. The ((230/7000)/.308^2)) would be the sectional density.
Upon looking some line up of bullets of the same caliber I see the BC proportionally increase with weight or sectional density. Could I make an assumption that the form factors of these bullets are very similar? This gets into comparing two bullets having equal BC's but different form factors and SD's. Like BC = SD/FF, given an increase in SD and a increase (not desirable) in FF could a lighter bullet have the same BC as a heavier bullet and the lighter bullet realize an advantage because it could be driven faster? Again, looking at the line up of same make bullets and same diameters and all having G7 BC's I am unable to find a lighter weight bullet having the same BC as a heavier bullet - I'm guessing the FF's are similar. Possibly, if I compared different makes of bullets I might be able to find 2 bullets of the same diameter and the same G7 BC but having different SD's and FF's and make an assumption that the lighter bullet with the lower FF should be selected because it could be driven faster.
That's right. It's a fudge factor relating the shape of the bullet to it's overall drag performance. It's not really a useful number for shooters - BC and weight are generally available.I thought that the G7 Form factor was-in Laymen terms basically "how efficient the BC is, so to speak...." The mass of an object can effect the BC but the G7 FF addresses the design effeciency...?
Anyone one care to put in their 2cents on that?
I fully agree with you that the goal should be having each bullets individual drag law available. Alas, apart from Lapua publishing such data first in 2009 (last updated 2015), manufacturers hesitate to publish their results. Bryan Litz also keeps the "custom drag" data under the wraps of the Applied Ballistics family of software.