Range Report Ballistic FTE G1 vs. G7

[bvt]

After messing around with my iphone with the Ballistic FTE. I was comparing the G1 vs. the G7. My current ammo is factory 168 GMM going about 2550 out of my 18" .308 (I know not ideal).

My question: when putting in elevation for 800 yds the G1 is 29.7 MOA vs. the G7 with 21.3 MOA. Why the huge difference?? I've read the G7 is a more accurate indication of trajectory. What gives?

 

[Saito]

Re: Ballistic FTE G1 vs. G7

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bvt</div><div class="ubbcode-body">After messing around with my iphone with the Ballistic FTE. I was comparing the G1 vs. the G7. My current ammo is factory 168 GMM going about 2550 out of my 18" .308 (I know not ideal).

My question: when putting in elevation for 800 yds the G1 is 29.7 MOA vs. the G7 with 21.3 MOA. Why the huge difference?? I've read the G7 is a more accurate indication of trajectory. What gives? </div></div>

http://www.snipershide.com/forum/ubbthre...257#Post1007257

Get Bryan's books....read them. That is all.

 

[Lowlight]

Re: Ballistic FTE G1 vs. G7

You're doing something wrong that is too much of a difference to be an issue of G1 vs G7

You inputted something incorrectly

 

[redirt78]

Re: Ballistic FTE G1 vs. G7

Kinda crazy that when I clicked on this thread the Applied Ballistics sponsor add was right under the post.

<span style="font-family: 'Arial Black'"><span style="color: #3333FF">APLLIEDBALLISTICSLLC.COM</span></span>

Tons of good info in Litz book, I just started it.

 

[Lowlight]

Re: Ballistic FTE G1 vs. G7

and there is no way an 18" 308 is using 21. MOA, that is closer to 700 yards for a normal 308, so clearly there is an error in what you are using. Especially at sea level.

The 29 MOA number is probably closer to right than 21 MOA, you try using that and the bullet will hit the ground around 700 yards if not a touch sooner.

 

[5RWill]

Re: Ballistic FTE G1 vs. G7

Lately i've been a little questionable about my FTE results. I guess i'm doing something wrong but it's always been very close with JBM. And looking the other day after entering my atmospheric conditions and my load for my MK12 Mod 1 it was giving me a output of 12.3 MOA to 600yds while JBM was calling 17.3. Ended up purchasing "shooter" app for my phone and it also called for 17.3. Thats the only mishap i've ever had with FTE and i know it has to be me. With what everyone else has said re check everything.

Isn't there a setting in FTE to use his engine or JBM?

 

[azimutha]

Re: Ballistic FTE G1 vs. G7

I think a lot of the errors encountered with Ballistic (or the FTE) version is the insistence of the developer in putting in both a Zero Atmosphere and a Current Atmosphere form. Turn off Zero Atmosphere and just use the Current Atmosphere settings.

As for the original question since it relates to any ballistic calculator, G7 for a boat tail will be more accurate once out past 500-600 yards. But there should not be that much difference @ 800. With my current load, a quick check shows 24 MOA (G7) vs. 24.1 (G1) @ 800 yards. As suggested, pay careful attention the inputs.

 

[Lowlight]

Re: Ballistic FTE G1 vs. G7

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: azimutha</div><div class="ubbcode-body">
As for the original question since it relates to any ballistic calculator, <span style="font-style: italic">G7 for a boat tail will be more accurate once out past 500-600 yards.</span> But there should not be that much difference @ 800. With my current load, a quick check shows 24 MOA (G7) vs. 24.1 (G1) @ 800 yards. As suggested, pay careful attention the inputs.</div></div>

Theoretically more accurate and not really until the bullet reaches transonic ... this breakdown clearly shows they are both equally accurate when used correctly.

 

[mouse07410]

Re: Ballistic FTE G1 vs. G7

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">Theoretically more accurate and not really until the bullet reaches transonic ... this breakdown clearly shows they are both equally accurate when used correctly.</div></div>
The output you posted comes from a program that doesn't follow either G1 or G7 approximation, but its own modified/combined approach - probably with Pejsa thrown in as well. The fact that it can come up with a correct answer regardless of what starting point you give it (G1 or G7) speaks well of LB3, but <span style="text-decoration: underline">has little to do</span> with how closely <span style="text-decoration: underline">G1 or G7 standard</span> projectiles model the currently used BT long-range bullets.

 

[Lowlight]

Re: Ballistic FTE G1 vs. G7

Shoot them...

It's pretty easy to see that i can get just as accurate with programs like BulletFlight using G1 as I do with G7... it's not that difficult to test and see for yourself. The benefit is in the transonic range, not as much supersonic.

People complain they can't get their dope to match up either way, so clearly it is more about actually shooting it and seeing than guessing behind a computer.

I shot FFS using G1 to 2100 yards and was well within .1 mils out to distance.

 

[Timo Turl]

Re: Ballistic FTE G1 vs. G7

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">Shoot them...

It's pretty easy to see that i can get just as accurate with programs like BulletFlight using G1 as I do with G7... it's not that difficult to test and see for yourself. The benefit is in the transonic range, not as much supersonic.

People complain they can't get their dope to match up either way, so clearly it is more about actually shooting it and seeing than guessing behind a computer.

I shot FFS using G1 to 2100 yards and was well within .1 mils out to distance. </div></div>

So without wishing to put words in your mouth are you saying that to most shooters it doesn't really matter whether the starting point is G1 or G7 ? I appreciate the need to match dope but assuming a first shot at a location/environment you have no experience or proven dope for then the diff between G1 and G7 (again for most shooters) isn't material ?

 

[Lindy]

Re: Ballistic FTE G1 vs. G7

The theoretical advantage of G7 is that it provides a superior calculation of velocity downrange. This may be an advantage with respect to knowing when the bullet is approaching the transonic region - but that may not be much of an advantage to a working sniper, who is probably going to attempt a shot irrespective of whether it's in that region.

A <span style="font-style: italic">partial</span> list of possible problems with any ballistic calculation is contained in Sources of Ballistic Program Inaccuracies. The second to last paragraph in that documents says:

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">A ballistic program is correctly used to get you close to that first-round hit under conditions you don't normally shoot in.</div></div>

Expecting dead-on predictions is simply unrealistic and ignores the factors listed in the article.

 

[bvt]

Re: Ballistic FTE G1 vs. G7

Thanks gents. In no way did I believe the G7 bc. The "current atmosphere" is activated for both my G1 and G7 bc's. All other data appears the same. I used the zero data for both bc profiles- with no other variables. My "iphone force" must be weak.

Maybe I'll try the Shooter ballistic calculator too.

I agree about the comment regarding Litz's book- will do.

 

[jbmillard]

Re: Ballistic FTE G1 vs. G7

Just out of curiosity, what was were the BCs you used for the G7 and G1 drag functions?

Brad

 

[bvt]

Re: Ballistic FTE G1 vs. G7

Let me be clear. This is not a bash on the product and I don't want this post to come across like that or turn into something like that. I've seen that happen time and again.

Brad, PM inbound.

 

[Lowlight]

Re: Ballistic FTE G1 vs. G7

FYI,

I just ran the numbers using Ballistics and the 168 with your MV, if you use G1 and then change the G1 to G7 without changing the actual number to the correct G7 BC, I get the same results you did.

I don't think any of us are saying you're blaming the program, however I do believe there is some operator error at work.

On certain occasions I use G7 too, but not all the time, and my results work the same downrange no matter which I use. Most of the time I actually set up the software to match my system regardless of the BC type, so this helps me however I will note that we have been using G1 for a very long time, and there were accurate ballistic calculation prior to Bryan releasing his G7 data, in fact a lot of software has only added G7 in recent years and their libraries are still light so it is often easier to get the G1 so... heck I think Gerald Perry still refuses to add it and ExBal was one of the original ballistic calculators.

Also as to the comment regarding Loadbase... if the models work, how his engine processes them should not matter. Because Gus is not using the same Point Mass Solver only goes to show you, 2+2 = 4, but so does 3+1, 4+0 , etc... it's the results down range that matter not how the solver gets there. Calling foul because it's using it's own engine is just silly.

An accurate solution can be had no matter what BC type you use, we have tons of G1 data, which makes it easy, as I have found the need to adjust the G7 from time to time too.. not as often, but even once is an clue.

 

[Ratbert]

Re: Ballistic FTE G1 vs. G7

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">

I just ran the numbers using Ballistics and the 168 with your MV, if you use G1 and then change the G1 to G7 without changing the actual number to the correct G7 BC, I get the same results you did.
</div></div>

Bwhahahahahahaha... snort... gasp.... ha.

 

[bvt]

Re: Ballistic FTE G1 vs. G7

Just trying to be civil and constructive, thats all. I see too many threads turn into something they were never intended to.

"however I do believe there is some operator error at work". ha definitely agree. No claims here on expertise, thats for sure.

To be honest, I thought it was something I was doing wrong from the start.

 

[Lowlight]

Re: Ballistic FTE G1 vs. G7

It's constructive,

Any mistake discussed might save someone else from making the same mistake.

No harm, no foul, it happens everyday.

 

[jbmillard]

Re: Ballistic FTE G1 vs. G7

If you're using the same number with two different drag functions, that's your problem.

The drag on the bullet is proportional to G/C where G is the value of the drag function (a function of velocity or mach number) and C is the ballistic coefficient. For the same drag force and different drag functions, the BC must be different. It doesn't make any sense to use a G1 BC with the G7 drag function.

You can read more about it here:

JBM - Topics - Drag Functions

This is really a pretty common mistake for those that don't work with many drag functions. I get emails about this all the time.

Brad

 

[Leaddog]

Re: Ballistic FTE G1 vs. G7

Just another reminder to log your conditions and dope in a databook. Over time, this information will be more valuable and specific to your rifle than any ballistic program.

The iPhone has a settings function for each program that should be configured. This is independent of the inputs that you enter directly into the program.

Having used Bulletflight, FTE, and Shooter, I prefer Shooter. Oh yeah... I use the G7 function for the Berger 185 LRBT's that I shoot.

 

[Lowlight]

Re: Ballistic FTE G1 vs. G7

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Leaddog</div><div class="ubbcode-body">Just another reminder to log your conditions and dope in a databook. Over time, this information will be more valuable and specific to your rifle than any ballistic program.

The iPhone has a settings function for each program that should be configured. This is independent of the inputs that you enter directly into the program.

Having used Bulletflight, FTE, and Shooter, I prefer Shooter. Oh yeah... I use the G7 function for the Berger 185 LRBT's that I shoot.



</div></div>

That makes sense, using G7 for a Berger bullet, but the question begs did you actually take the time to set up the system by calibrating the scope and confirming the drop? Or did you just add the BC, MV and go... Shooting F Class the need for a ballistic computer is pretty rare, so I would also ask, in the past before the numbers given for G7 were available, did you find G1 not working?

I posted this in reference which was independently verified...
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=3022669#Post3022669

I shoot Berger bullets too and use G7 it does make sense, and is a good average number, but I also get great accuracy because I set up the system to the bullet and rifle. This includes adjusting the G7 if necessary, the same exact way I adjust G1. (though I tend to band G1 because of the data available which I find works well)

But clearly based on the data I have from 3rd parties Point Mass solvers don't handle unadjusted data as well, especially G1. Which is why out of the gate the G7 works better with those ballistic engines. So a person can see a difference when using one of these programs, however, adjusted data is equally accurate if you take the time to set it up right.

 

[Leaddog]

Re: Ballistic FTE G1 vs. G7

Frank - When I was spending more time shooting with Vern and running a NF 5.5-22, I did spend the time to check my scope calibration and drop. I also spent more time with my Chrono and knew exactly what I was shooting (35P). Using that information and adjusting my ballistic's program (FTE at the time), I had good, repeatable, real time data.

I agree with you regarding F Class. Shooting KD, this kind of data isn't so important anymore. Shoot 2 sighters, dial it, and hammer the 10 ring. I'm one of the rare F Class shooters that still pulls out a Kestrel and records the conditions with each relay anyway. It's just the way I was taught to shoot.

As for scopes, I shoot a MOA/MOA 12-42 NF NXS and a MOA/MOA March 10-60 Tactical these days. Although the March has outstanding glass, I would never consider it for anything tactical or unknown range shooting. The eye relief is super critical and slows down target acquisition. It is much better at home on a KD range. BR or F Class.