G1 vs G7 Drag For Long Range Bullets

[LongRangeMike]

I've got the rifle and scope setup for some long distance shooting and I'm getting ready to start 1000+ yard shooting. So I just started taking my crono / bullet data looking to get some solid ballistic data.

Here is what through me off, I was wanting to test the accuracy of some of the ballistic tools I've gathered (Excel one from this website and online ones such as Hornady). Using the online Hornady one I couldn't believe the difference when using G1 vs G7 and wanted to know what those of you in these forums use.

Using the G1 function my bullets would have ~384 ft/lbs of force at 1750 (~1 mile) but with G7 it's well over 1100 ft/lbs of force and the drop difference is significant.

What say you if you have experience at this range?

FYI
3740 FPS, 180 Grain .475 B/C - 1.5" Sight Above the Barrel, 200 Yard Zero

[JackinSD]

Quick question: What did you use for your G7 BC?

Here is a little information on the differences of the G1 and G7 BC.

http://bulletin.accurateshooter.com/...-need-to-know/

[Broz]

If you are using the same number (the .475) for both a G1 and a G7 profile that is incorrect. The .475 would be a G1 rating for a 180 I would guess, but you need the G7 BC number for that bullet to use a G7 model.

Jeff

[LongRangeMike]

Originally Posted by JackinSD

Quick question: What did you use for your G7 BC?

Here is a little information on the differences of the G1 and G7 BC.

G1 vs. G7 Ballistic Coefficients — What You Need to Know « Daily Bulletin

Thanks for the link but I'm a little more lost now because I'm not sure if Nosler references to G1 or G7.
I use the same B/C for both... might be the issue. I use 165 and 180 grain Nosler BST. I got the BST from the Nosler website on the bullets. And correction my Velocities were for the 165, not the 180.
B/C for 165 Grain is .475 for the BST Spitzer
B/C for 180 Grain is .507 ''....
Ballistic Tip - Nosler - Bullets, Ammunition, Rifles, Brass, Reloading Data, Hunting, Shooting, Reloading, Load Data
Not sure if those are referenced to G1 or G7... But need to know.

[Broz]

Originally Posted by LongRangeMike

Not sure if those are referenced to G1 or G7... But need to know.

Looks like G1 Bc's to me

Jeff

[LongRangeMike]

Thanks, I asked Nosler through their website so we'll see what they say. But using the same B/C will yield crazy results. Bullets in my gun are expensive even when reloaded so I want to at least be close at long ranges so I can make adjustments with fewer rounds fired.

Thanks

[JackinSD]

Sorry Mike. Wasn't trying to confuse you.

The point I was trying to get across, as I knew your problem, was that you were using the G1 BC for both.