Comments on: G1 vs. G7 Ballistic Coefficients — What You Need to Know

By: VF

VF — Tue, 23 Jun 2020 09:22:30 +0000

There are not places I can shoot to even 300 yards. So none of this really matters-lol.
Long range ballistics knowledge takes rifle shooting to a whole different level. Though I do find it all interesting . Now all I have to do is go buy expensive precision rifles ,scopes, rangefinders, etc.; and spend even more money to travel to places to shoot.

By: Jamie

Jamie — Mon, 02 Sep 2019 21:21:12 +0000

Hey John,
I’m new too. I have usually hunted pigs with dogs and a knife. Getting older now…
I agree with the shooting where my rangefinder and ballistics calculator tell me a bit is. I’ve had a lot of success with G7 Hornady 7mm ELD-X rounds using the App, Streylock Pro as the Ballistics calculator.
You need your barrel length and twist rate for accurate calculations. A good bi-pod makes easy 500yard shots.
Hope that’s useful.
Jamie

By: John

John — Sun, 27 Jan 2019 10:36:51 +0000

Sorry guys. I am a new shooter, just learning the ropes but I can tell you what I have found is that there are lots of shooters out there who know very little, even less than me.

I dont understand. Who cares, g1 or g7. All I want is a model that matches my rifle and my load so when I dial the elevation in to my scope, the bullet lands where I expect.

Can anyone help?

By: Dana Webb

Dana Webb — Tue, 23 Oct 2018 02:46:35 +0000

My understanding of ballistics coefficient is that it is a coefficient of the ratio between a standard bullet and usually a smaller bullet of interest and it should stay close to constant, the standard bullet which is has the two-caliber radius ogival head and flat base is used to produce the G1 drag function, this bullet also has a specific form factor and is related specifically to the G1 drag function. You can multiply this function by about one half .497 and use G7 ballistics coefficient which will give you about the same results as just using the G1 with G1 ballistics coefficients. So, by this approach you’re not using the G7 ballistics function you’re just getting G1 results with G7 Coefficients.
In Hatchers note book there are tables on page 566 there is a table with different drag functions with their retardation at certain velocity increments, the Aberdeen J drag function is one were they use a boa tailed spitzer bullets for the standard Bullet which will give a closer approximation to the G7 drag function. Happy calculations.

By: Craig Swenson

Craig Swenson — Thu, 26 Jul 2018 04:27:39 +0000

My Comment: Mac Lorry’s comment in 2013 is interesting. He cites that trivial small difference between G1 and G7 BCs. I tried an on-line ballistic calculator with both G1 and G7 BCs at http://gundata.org/ballistic-calculator/.
I input 300 Win Mag 180 Grain Winchester Ballistic Silvertip bullets (recommended by rifle manufacturer Savage 111) and ran the calculator with both G1 and G7 BCs. The differences were profound. For the G1 calculation (BC=.508) the drop is 46″ and 283″ for 500 yds and 1000 yds, respectively. For the G7 calculation (BC assumed ~ G1/2 = 0.2535) the drop is 46″ and 283″ for 500 yds and 1000 yds, respectively. By this calculator and this cartridge & bullet, the G1 and G7 are equal. So, the G1 vs G7 BC gets more confusing. For any equation of fluids, velocity applicability limits have to be involved. I would like to see the actual equations and the limits or parameters like in engineering or any other technical field.

By: Craig Swenson

Craig Swenson — Wed, 25 Jul 2018 04:08:46 +0000

I agree with Lester. I am licensed PE in mech engineering and civil engineering. I can’t cite the number of times that I have been confronted by non-engineer technicians or technologists and their disdain for engineers. It is a no-win situation if management is technically clueless. One should read the Standard Occupation Classifications published by the government. Hands-on vs analytical and build tools vs inspection tools matter. I am glad lots of testing happens. It is sometimes better than pure analysis, but every circumstance must be tested rather predicted by scientific equations.
https://www.bls.gov/soc/2018/major_groups.htm#17-0000

By: Chris-NZ

Chris-NZ — Sat, 18 Nov 2017 18:24:37 +0000

Halving a G1 to estimate G7 is rather crude. Most G7s seem to be about 55% of G1

By: IAC.

IAC. — Thu, 16 Nov 2017 03:07:21 +0000

@Sambo- It,s G1 @ .462/.464 depending on the website.
I double checked a few sites, but the ammo companies publish the G1 number because it,s so much higher (read impressive)!
G7s are more in the .100 to .200 range.

By: Sambo

Sambo — Mon, 26 Jun 2017 23:51:36 +0000

I landed here just because I am trying to figure out if federal used G1 or G7 when they calculated their BC on their .308 168-grain sierra matchking BTHP rounds. anyone know? thanks!

By: Max

Max — Sun, 04 Jun 2017 17:43:08 +0000

7mmmag 150 in Remington gun is g what ¿