G7 drag model

[7mmXBOLT]

I was curious if Nosler has a G7 drag model conversion for their pointed boat tail bullets? They use and list a G1 drag model for the BC of their bullets that is only close enough to minute of deer. I would like something more precise that I can use in my ballistic program if it is possible.

Need it for the CT - 85 grain .257 & CT - 140 grain .284

Can someone point me in the right direction please?

Thanks Bill

 

[Desert Fox]

Berger is the only US bullet manufacturers that list their B.C base of the G-7 drag model. What type of ballistic program you're using?

 

[7mmXBOLT]

I have been using the paid version of Shoot3.2 but have ordered RCBS load and it is on the way and would love to be able to use the G7 drag model.

Does Nosler have any plans on following suit with Berger? I know it has everything to do with marketing but come on let's be real here. For the short range, game hunter the G1 is good enough. What about the long-range hunter or competition shooter who would prefer using something a little more precise.

I believe most people are like myself in that if you give it to me straight, I will be a loyal customer for life. I do use Berger bullets particularly their VLD match and hunting VLD bullets in a few calibers but Nosler bullets have proved to me to be a very accurate bullet. I found the CT bullet to be more consistently accurate than the Berger VLD in more than one caliber I load for. A good thing! However, all this scope tweaking is getting old fast. I commend Berger for their attempt to be straightforward with their advertised BC by giving us something that helps get to the accuracy level their bullets are truly capable of. I believe they have sold more bullets this way myself. I also feel if Nosler were to do the same the trend would weed out the good bullet manufactures from the bad.

Not trying to rock the boat here but if Nosler where to give me the appropriate BC for their spitzer boat tail bullets then I have a far greater chance of a one shot kill at virtually any distance. To me, that opens shooters eye's more than anything else and in all respect to our quarry it is the least we can do for taking it’s life.

Just a thought! :roll:


Bill

 

[Desert Fox]

How far are you going to shoot! Is your program accept G-7 B.C only? Noslers, Sierra, Speer and Barnes all published B.C base on G-1 drag model and their fairly accurate at reasonable hunting distances. Unless your shooting at extreme long ranges, I don't think it matters much. You have to understand that publish B.C data by the manufacturers are not static. They're just your baseline. Bullet B.C can be affected by all sorts of variables and environmental conditions so it can change. Most of the time it requires tweaking in the field to validate your actual result. Sometimes you can be as lucky as I am with my 338 Lapua Ackley Improved that the bullet publish B.C can be spot-on and doesn't require any tweaking. I had it verified by shooting at target up to 1600 yards.

I have been using the paid version of Shoot3.2 but have ordered RCBS load and it is on the way and would love to be able to use the G7 drag model.

JBM does the same thing and it's free.

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.0.cgi

 

[30-338]

If you go over to http://www.longrangehunting.com/. Last year Berger going into a contest with Barnes over some comment post on there site about Berger VLD hunting bullets. It got into a big mess just like a bunch of kids and Berger just decide to one up Barnes putting the G-7 BC on their labels.

Since Barnes has sold out their old web site downl. Berger last year redid most BC on the bullets after they hired Bryan Lutz and the G-7 was his idea here the article
http://www.longrangehunting.com/article ... ient-1.php

 

[Richracer1]

There's also an article on the Berger website about the BC ratings. The jist of it is, we have been brought up on the G1 specs and are use to the higher numbers. I agree, the G7 scale better represents current hunting bullet shapes, but people aren't going to buy a .250 - .300 BC (G7) rated bullet, we want to see the .500 - .700 BC (G1) rated bullet.

I would love to see the bullet manufacturers initially start advertising both G1 and G7 BCs for their bullets. In time they can switch over to just using the G7 on those type of bullets.

 

[7mmXBOLT]

So I would assume the quick answer would no, no plans, nada?

You all make valid points and I do realize there are people on both sides of the fence here however, do we really think any bullet manufacture would loose client base by simply sliding in the G7 along side the G1 advertised value? I would think this would satisfy everyone. I have a feeling when their testing these types of bullets they are using the G7 to begin with. I could be wrong but that would make sense to me anyways. Not to mention I would also think anyone who hand loads understands there is a difference however slight it may be especially if they are concerned with the BC to begin with. The short-range shooter needs not to concern him or herself with it but the long-range shooter could certainly benefit. The further out your shooting the more it is magnified even if it is just a base line. We can control atmospheric condition to some degree within our ballistic programs but you plug in a BC value that does not totally represent the bullet profile and your already coming out of the hole out of wack. Believe me at 500-600 yards there is a difference that is noticeable.

I guess I would like to hear Noslers take on this.

 

[DrMike]

7mmXBOLT,

Have you tried contacting Nosler directly with your question? They provide for contact via Email and/or phone (http://nosler.com/contactus.htm).

 

[7mmXBOLT]

Actually, I have not. I know some of the techs are site monitors and was hoping one might chime in. If I don't get an answer, I will give them a ring.

Thanks DrMike for the infomation.


Bill

 

[Ridge_Runner]

well no matter what the makers tell you about the bc, it'll be different for you. each barrel shoots a differnt BC with the same bullet, not much different but some. its easy to find out what your actual BC is just with 1 range session.
The numbers get you close its up to you to figure what your BC is, I do pretty well using the G1, just tune your charts to your actual trajectory, your making it harder than it has to be.
RR

 

[7mmXBOLT]

well no matter what the makers tell you about the bc, it'll be different for you. each barrel shoots a differnt BC with the same bullet, not much different but some. its easy to find out what your actual BC is just with 1 range session.
The numbers get you close its up to you to figure what your BC is, I do pretty well using the G1, just tune your charts to your actual trajectory, your making it harder than it has to be.
RR

Understand I mean no disrespect here and I agree with most of what your saying but this has nothing to do with trying to make things harder than it needs to be and everything to do with trying to make things easier like it should be. Trust me if you have used the proper BC within the drag model it is designed for you would know things go far more smoother.

My guess is there is no G7 BC data available and not likely to be anytime soon.

Thanks for all your help.

Bill

 

[Ridge_Runner]

Don't know how things could as you say go smoother, Its a pretty simple task figuring your actual BC. after all you have your complete set of data with the exception of your BC.
I've never had a problem using the G1 drag function shooting nosler accubonds. I've killed every deer I've shot at at extended ranges out to 1350 yards using a G1, and its not the number nosler publishes.
Like I said that published number is just a place to start. You have to tweak it so your chart matches your actual trajectory under your shooting conditions with your rifle.
Nosler publishes the BC of a 160 AccuBond at .531, to make my charts match my actual trajectory I have to use .62 in my program to make POI and POA match out to 1400 yards.
How much smoother go ya need it?
RR

 

[JD338]

I use the G1 drag model with Nosler bullets. As already mentioned, there are a lot of variables in determining a BC. Nosler's listed BC is an average.

JD338

 

[nodak7mm]

I am with Desert Fox, JD338 & others as I use the std G1 model and it works great for me. RidgeRunner however summed it up the best as I also believe you need to go test the bullet under the conditions and match your field findings to a computer model in order for it to be useful. So both the G1 & G7 BC figures are as JD said, a reference point. You need to real world test to find "your" actual

That said, there is no magic computer model that is necessarily more simple or more accurate than the other as it is all based on mathmatical formulas in the first place. I take that back in the regards that there are basic programs which limit the varibles and there complex programs that give you the option of entering every possible varible. The key to remember is that the bullet BC is only one varible.

I am by no means a mathematician and really suck at math, but have been using ballistics programs since the early 90's and they are a great and useful tool, but we need to remember, they are just a computer model that gives us an approximation.. Real field conditions testing with the assistance of a computer based model is best..

Boy I kinda went off on a tangent there didnt I? Fyi, I currently use the Sierra program and like it, before that I used the Oehler ballistics lab program..

Good luck with which ever you prefer as it is your choice and either will work well for ya. 8)

 

[JD338]

I might add that I use the ballistics calculator (advanced calculator) below and it is close but not absolute.

http://www.biggameinfo.com/BalCalc.aspx

Beyond 400 yds, I may have to adjust by 1-2 come ups to be dead on with my zero. Temp and humidity do play a role based on the BC value I use. By changing the BC value, I can usually match the drop.

JD338

 

[CAhunter]

Ridge Runner. I was wondering if you could explain in brief how you find your bc for a certain rifle. I am in the process of loading for my 30-378 with 200gr accubonds and 180. I am trying to get some custom turrets built as well. Once I get my load accuracy set. Just wondering as this is my first attempt at getting turrets. What are you thoughts??

Thanks

 

[JD338]

CAhunter

What make and model scope are you using? The custom turrets you are referring to, do you mean BDC dials etched to your loads?

The reason I ask is that you want to make sure you have a scope with repeatability. You can dial up or down and return to absolute zero.

You will also need a chronograph to get your MV.
Your 30-378 with a 200 gr AB will certainly be able to reach out there and hammer game at long range! :grin:

JD338

 

[Ridge_Runner]

Ok, first I want to say the custom BDC knobs work pretty well to 700 yards, beyond that your current conditions effect trajectory enough that they have to be taken into account.

To find your actual BC
get all your data that you are in control of as close as possible
(MV, heigth of scope)
Now sight in at 300 yards
shoot at 400, 500, and 600 yards measure your actual drops
run the numbers with the published BC.

so you know your MV is correct, the heigth of your scope, the Bar pressure, and temp, all that is correct, so if your POI and POA doesn't jive its got to be BC, so change the BC in your program till the chart matches your actual drops that is your actual BC. Its that easy!
RR

Don't worry about humidity, from 0% to 100% only amounts to about 2" change in POI at 1K

 

[CAhunter]

Thanks guys!! The scope is a leupold 6.5x20x50LR. I think it should be pretty good. I do have a chrony. I was looking into the kenton turrets.. what do you guys recommend I do? Turrets or reticle or what?

 

[JD338]

CAhunter,

Great choice in a scope.
For shooting 500 yds and closer, you can go with the B&C reticle. Mil Dot is good IF you learn how to use it. IMO, dials are the way to go. Once you have your range determined (a good LRF is a must), refer to your drop chart and make your adjustments.
I would send the scope back to the Leupold Custom Shop and have them install the M 1 dials. They are very robust and any adjustment made is positive. Cost is around $150 and turn around time is usually under 10 days.

I have had M 1 dials installed on two scopes and they are great. I had concerns about them getting bumped, moved, etc., not to mention that they would be exposed to the elements. They are very robust and I have not had a single issue with them.

JD338