Range Report At what range is g7 better then g1? Anyone know?
- Thread starter Ring
- Start date
Re: At what range is g7 better then g1? Anyone know?
The calculations on G1 BCs seem to overstate the terminal velocities - the G7 BCs seem to be more accurate with velocities at longer distances. That's mostly important when consider the point where bullets get into the transonic region, when they may exhibit unpredictable behaviour.
The calculations on G1 BCs seem to overstate the terminal velocities - the G7 BCs seem to be more accurate with velocities at longer distances. That's mostly important when consider the point where bullets get into the transonic region, when they may exhibit unpredictable behaviour.
Re: At what range is g7 better then g1? Anyone know?
Good answer on predicted velocity, Lindy.
Predicted kinetic energy goes hand-in-hand with velocity.
Ring,
If you're interested in the differences in predicted drop between G1 and G7, I use ~500 yards as a rule of thumb. Up to 500 yards, the difference in the predicted trajectory can be considered minor (one or two 1/4 MOA clicks). Beyond that, the error can grow into something more significant.
It's somewhat related to caliber too. If you're shooting 70 grain bullets from a .223, you'll see a bigger difference at a much shorter range than if you're shooting 300's from a .338.
Good question.
-Bryan
Good answer on predicted velocity, Lindy.
Predicted kinetic energy goes hand-in-hand with velocity.
Ring,
If you're interested in the differences in predicted drop between G1 and G7, I use ~500 yards as a rule of thumb. Up to 500 yards, the difference in the predicted trajectory can be considered minor (one or two 1/4 MOA clicks). Beyond that, the error can grow into something more significant.
It's somewhat related to caliber too. If you're shooting 70 grain bullets from a .223, you'll see a bigger difference at a much shorter range than if you're shooting 300's from a .338.
Good question.
-Bryan
Re: At what range is g7 better then g1? Anyone know?
And there's the answer from someone who knows. Ring, if you're seriously interested in such subjects, allow me to recommend Bryan's book.. It's full of essential information for anyone shooting long distance. You can find some such information elsewhere, but it's handy to have it in one place. And his information about BCs, especially G7 BCs, cannot be found elsewhere.
And there's the answer from someone who knows. Ring, if you're seriously interested in such subjects, allow me to recommend Bryan's book.. It's full of essential information for anyone shooting long distance. You can find some such information elsewhere, but it's handy to have it in one place. And his information about BCs, especially G7 BCs, cannot be found elsewhere.
Re: At what range is g7 better then g1? Anyone know?
I had a play comparing Bryan's G7 prediction for the 155scenar against lapua's doppler data (under the same environmetal condition inputs).
It's pretty stunning out to around 700m -that is, for all practical purposes, SPOT ON (ie as good as doppler Cd data).
Then a smidge optimistic to 900; but still within 2 or 3 x 0.1mRad clicks -which is still pretty stunning for an approximation.
Untweaked G1 wouldn't get close to this. Impressive
[I suppose it's worth bearing in mind that 155 scenar is something of a 'best of breed' for a good G7 fit; anything less 'VLDish' would diverge sooner/more.]
[
[Ignore ranges over 900m (which are clearly silly for a 308 -I put them in out of interest
]
I had a play comparing Bryan's G7 prediction for the 155scenar against lapua's doppler data (under the same environmetal condition inputs).
It's pretty stunning out to around 700m -that is, for all practical purposes, SPOT ON (ie as good as doppler Cd data).
Then a smidge optimistic to 900; but still within 2 or 3 x 0.1mRad clicks -which is still pretty stunning for an approximation.
Untweaked G1 wouldn't get close to this. Impressive
[I suppose it's worth bearing in mind that 155 scenar is something of a 'best of breed' for a good G7 fit; anything less 'VLDish' would diverge sooner/more.]
[Ignore ranges over 900m (which are clearly silly for a 308 -I put them in out of interest
Re: At what range is g7 better then g1? Anyone know?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ring</div><div class="ubbcode-body">At what range is g7 better then g1? </div></div>
If a bullet has a shape similar to the G7 shape, then the G7 BC is more accurate for that bullet over any range.
If a bullet has a shape similar to the G1 shape, then teh G1 BC is moe accurate for that bullet over any range.
But for many practical purposes, little of this maters inside 500 yards or so.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ring</div><div class="ubbcode-body">At what range is g7 better then g1? </div></div>
If a bullet has a shape similar to the G7 shape, then the G7 BC is more accurate for that bullet over any range.
If a bullet has a shape similar to the G1 shape, then teh G1 BC is moe accurate for that bullet over any range.
But for many practical purposes, little of this maters inside 500 yards or so.
Re: At what range is g7 better then g1? Anyone know?
True. But hardly anyone is shooting a bullet which resembles the G1 model in a precision rifle.
True. But hardly anyone is shooting a bullet which resembles the G1 model in a precision rifle.
Re: At what range is g7 better then g1? Anyone know?
When I started using the G7 BC's, my data was spot on to 1K. When I was using G1 BC's, I would get odd elevation variations at longer distances and not know why. Now, I only use G7's for my personal loads and my customers' trajectory data.
When I started using the G7 BC's, my data was spot on to 1K. When I was using G1 BC's, I would get odd elevation variations at longer distances and not know why. Now, I only use G7's for my personal loads and my customers' trajectory data.
Re: At what range is g7 better then g1? Anyone know?
I'm looking foward to reading Mr Litz book, should be here Monday or Tuesday, G7 is the way to go, when using JBM always select the bullets that have Bryan Litz next to them if possible.
I'm looking foward to reading Mr Litz book, should be here Monday or Tuesday, G7 is the way to go, when using JBM always select the bullets that have Bryan Litz next to them if possible.
Re: At what range is g7 better then g1? Anyone know?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">True. But hardly anyone is shooting a bullet which resembles the G1 model in a precision rifle.
</div></div>
Which begs the question as to why so many bullet BCs are found in the G1 drag model.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">True. But hardly anyone is shooting a bullet which resembles the G1 model in a precision rifle.
</div></div>
Which begs the question as to why so many bullet BCs are found in the G1 drag model.
Re: At what range is g7 better then g1? Anyone know?
That's easy. Until fairly recently there were few if any programs which could utilize a G7 BC, so there was pretty much no demand.
That's easy. Until fairly recently there were few if any programs which could utilize a G7 BC, so there was pretty much no demand.
Re: At what range is g7 better then g1? Anyone know?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">That's easy. Until fairly recently there were few if any programs which could utilize a G7 BC, so there was pretty much no demand. </div></div>
In addition to that, shooting equipment wasn't at the point where the benefit could be resolved as well as it can now. What good is a trajectory calculation that's 2" more accurate at 400 yards when you're estimating range based on counting fence posts, 'gauging' temperature on feel, guessing at muzzle velocity based on the load manual, and shooting a rifle that would be lucky to shoot a 1 MOA group.
The relatively recent advent of portable weather stations (like Kestrels), laser rangefinders, and truly accurate rifles to the sporting arms industry have made the small errors in G1 based trajectory predictions a significant weakness in the 'kill chain'. The benefits of properly referenced G7 BC's are evident today, but may not have been as significant 10 years ago.
There's also an argument to be made that since the value of a BC referenced to the G1 standard is numerically greater, that there is marketing value in using it, even though it's not the 'best information'.
Probably the real reason G1 hung around so long is the complacent attitude of: "That's how we've always done it".
I for one am very happy to see G7 BC's adopted and used because it's simply a more accurate way to predict trajectories. It will result in more holes in distant targets.
Cheers,
-Bryan
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">That's easy. Until fairly recently there were few if any programs which could utilize a G7 BC, so there was pretty much no demand. </div></div>
In addition to that, shooting equipment wasn't at the point where the benefit could be resolved as well as it can now. What good is a trajectory calculation that's 2" more accurate at 400 yards when you're estimating range based on counting fence posts, 'gauging' temperature on feel, guessing at muzzle velocity based on the load manual, and shooting a rifle that would be lucky to shoot a 1 MOA group.
The relatively recent advent of portable weather stations (like Kestrels), laser rangefinders, and truly accurate rifles to the sporting arms industry have made the small errors in G1 based trajectory predictions a significant weakness in the 'kill chain'. The benefits of properly referenced G7 BC's are evident today, but may not have been as significant 10 years ago.
There's also an argument to be made that since the value of a BC referenced to the G1 standard is numerically greater, that there is marketing value in using it, even though it's not the 'best information'.
Probably the real reason G1 hung around so long is the complacent attitude of: "That's how we've always done it".
I for one am very happy to see G7 BC's adopted and used because it's simply a more accurate way to predict trajectories. It will result in more holes in distant targets.
Cheers,
-Bryan
Re: At what range is g7 better then g1? Anyone know?
I am begenning to regret the purchase of your book Bryan.
I will have to find some elaborate excuses to explain my misses!
Thanks!
I am begenning to regret the purchase of your book Bryan.
I will have to find some elaborate excuses to explain my misses!
Thanks!
Re: At what range is g7 better then g1? Anyone know?
You just need practice. Proper excuse management is an important competition technique. You have to develop them in advance, and stage them <span style="font-style: italic">prior</span> to missing the target.
You just need practice. Proper excuse management is an important competition technique. You have to develop them in advance, and stage them <span style="font-style: italic">prior</span> to missing the target.
Re: At what range is g7 better then g1? Anyone know?
A little off subject, I received Bryans book today, it's hard to put down, and I wasn't expecting a hardcover, very nice, thank you for your hardwork and dedication.
A little off subject, I received Bryans book today, it's hard to put down, and I wasn't expecting a hardcover, very nice, thank you for your hardwork and dedication.
Re: At what range is g7 better then g1? Anyone know?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">You just need practice. Proper excuse management is an important competition technique. You have to develop them in advance, and stage them <span style="font-style: italic">prior</span> to missing the target.</div></div>
I will buy your book when it comes out...
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">You just need practice. Proper excuse management is an important competition technique. You have to develop them in advance, and stage them <span style="font-style: italic">prior</span> to missing the target.</div></div>
I will buy your book when it comes out...
Re: At what range is g7 better then g1? Anyone know?
Thanks, but it's highly unlikely that I will write a book.
Writing is hard work for very little money. I'm opposed to hard work - it interferes with my program of sloth and indolence.
I have done some writing - the articles are listed here - but that was mostly in self-defense, to use for students, and to keep from having to write the same thing repeatedly on Sniper's Hide.
But thanks anyway!
Thanks, but it's highly unlikely that I will write a book.
Writing is hard work for very little money. I'm opposed to hard work - it interferes with my program of sloth and indolence.
I have done some writing - the articles are listed here - but that was mostly in self-defense, to use for students, and to keep from having to write the same thing repeatedly on Sniper's Hide.
But thanks anyway!
Re: At what range is g7 better then g1? Anyone know?
Bryan,
Excellent book on a topic that's easily overmathemicated. I can even stumble thru the math. You did an excellent job!
John
Bryan,
Excellent book on a topic that's easily overmathemicated. I can even stumble thru the math. You did an excellent job!
John
Re: At what range is g7 better then g1? Anyone know?
Brian's book is the best piece of ballistic information to come along in a decade.It makes a great christmas gift and true to his word Brian presents the material so you don't have to have an engineering degree to grasp the consepts.Is there a part two?
Brian's book is the best piece of ballistic information to come along in a decade.It makes a great christmas gift and true to his word Brian presents the material so you don't have to have an engineering degree to grasp the consepts.Is there a part two?
Re: At what range is g7 better then g1? Anyone know?
After scanning through Bryan's book while visiting Tony I threw it on the Christmas list and can't wait to get it in and read it. Looked like lots of good info and liked all the BC data.
That said I have always used the G1 for bullets and never been off more than a few tenths of a mil at 1000. Maybe I am lucky but it was close. This has been with Sierra, Berger and Hornady bullets. I want to run some G7 numbers and compare them to my actual data. Should be interesting.
After scanning through Bryan's book while visiting Tony I threw it on the Christmas list and can't wait to get it in and read it. Looked like lots of good info and liked all the BC data.
That said I have always used the G1 for bullets and never been off more than a few tenths of a mil at 1000. Maybe I am lucky but it was close. This has been with Sierra, Berger and Hornady bullets. I want to run some G7 numbers and compare them to my actual data. Should be interesting.
Re: At what range is g7 better then g1? Anyone k
In my experience, somewhere between 500 to 600 yards. At these ranges, the difference become readily apparent. For the most part the difference up to this point is just a click or two. After this point, the separation grows rapidly. The only exception to this that I have found is the 7 WSM I shoot with the 180 VLD @ 3000 fps. This combo will diverge a bit later (around 200 yards further). I live about a mile high, so things are somewhat different here, but the basic idea should the same.
I too have Bryan's book and for me it was like reading Hawking's book, "A brief history of time". He took every element of modern ballistics and shoehorned it into something even I can understand.
The only thing silly shooting a .308 past 900m is the grin I get on my face!
Seeing as how almost all of the bullets I shoot "fit" the G7 profile, I have converted ALL of my dope to this. I have an excellent load for the AR10T that I use hunting. The 180 Swift Scirocco with a G7 at 2645 fps. I used a 5 mil holdover for a 735 yard first round hit on steel before hunting season to confirm data. No more tweaking G1 functions to fit field data. I love it.
In my experience, somewhere between 500 to 600 yards. At these ranges, the difference become readily apparent. For the most part the difference up to this point is just a click or two. After this point, the separation grows rapidly. The only exception to this that I have found is the 7 WSM I shoot with the 180 VLD @ 3000 fps. This combo will diverge a bit later (around 200 yards further). I live about a mile high, so things are somewhat different here, but the basic idea should the same.
I too have Bryan's book and for me it was like reading Hawking's book, "A brief history of time". He took every element of modern ballistics and shoehorned it into something even I can understand.
The only thing silly shooting a .308 past 900m is the grin I get on my face!
Seeing as how almost all of the bullets I shoot "fit" the G7 profile, I have converted ALL of my dope to this. I have an excellent load for the AR10T that I use hunting. The 180 Swift Scirocco with a G7 at 2645 fps. I used a 5 mil holdover for a 735 yard first round hit on steel before hunting season to confirm data. No more tweaking G1 functions to fit field data. I love it.
Re: At what range is g7 better then g1? Anyone k
im useing G7 now for all my 400+ loads, all my lighter varmit stuff im still useing G1 400-
im useing G7 now for all my 400+ loads, all my lighter varmit stuff im still useing G1 400-
Re: At what range is g7 better then g1? Anyone k
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ring</div><div class="ubbcode-body">im useing G7 now for all my 400+ loads, all my lighter varmit stuff im still useing G1 400- </div></div>
Why??
If your ballistic program supports G7 coefficient drag models and you’re shooting boat tail bullets why use an obsolete drag model for your 400 yard or less shooting?
Hopefully you’re not relying on the published G1 BC’s from the bullet manufactures for this short range work. The published G1 BC’s may or may not be close out of your actual gun.
Bryan Litz has done much work testing and measuring actual G7 BC’s and his published G7 bullet library has proven to be accurate to within 1%. Published G1 BC’s can be off as much as 8% +/-. I realize its short range work but why not be as accurate as possible?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ring</div><div class="ubbcode-body">im useing G7 now for all my 400+ loads, all my lighter varmit stuff im still useing G1 400- </div></div>
Why??
If your ballistic program supports G7 coefficient drag models and you’re shooting boat tail bullets why use an obsolete drag model for your 400 yard or less shooting?
Hopefully you’re not relying on the published G1 BC’s from the bullet manufactures for this short range work. The published G1 BC’s may or may not be close out of your actual gun.
Bryan Litz has done much work testing and measuring actual G7 BC’s and his published G7 bullet library has proven to be accurate to within 1%. Published G1 BC’s can be off as much as 8% +/-. I realize its short range work but why not be as accurate as possible?
Re: At what range is g7 better then g1? Anyone k
What for? At those distances, you don't generally need a ballistic computer at all, as the dope isn't going to change much with conditions.
What for? At those distances, you don't generally need a ballistic computer at all, as the dope isn't going to change much with conditions.
Re: At what range is g7 better then g1? Anyone k
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">What for? At those distances, you don't generally need a ballistic computer at all, as the dope isn't going to change much with conditions.
</div></div>
Why ?? was for using the G1 drag model for shots under 400 yards.
I fully agree with your statement and point about your dope not changing much in those conditions. My point was if you're going to use a ballistic program you might as well use the proper drag model and BC regardless of whether you’re only shooting to 400 yards or your shooting longer distances. Stay consist as consistency drives better results…usually!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">What for? At those distances, you don't generally need a ballistic computer at all, as the dope isn't going to change much with conditions.
</div></div>
Why ?? was for using the G1 drag model for shots under 400 yards.
I fully agree with your statement and point about your dope not changing much in those conditions. My point was if you're going to use a ballistic program you might as well use the proper drag model and BC regardless of whether you’re only shooting to 400 yards or your shooting longer distances. Stay consist as consistency drives better results…usually!
Re: At what range is g7 better then g1? Anyone k
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">You just need practice. Proper excuse management is an important competition technique. You have to develop them in advance, and stage them <span style="font-style: italic">prior</span> to missing the target.
</div></div>
ALWAYS be prepared!!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">You just need practice. Proper excuse management is an important competition technique. You have to develop them in advance, and stage them <span style="font-style: italic">prior</span> to missing the target.
</div></div>
ALWAYS be prepared!!
Re: At what range is g7 better then g1? Anyone k
Does Mr. Litz have this bullet library in his book, or is it available somewhere else? I shoot 7mm/162gr A-max's and have some other brands to tinker with and I would like to know what the G7 values for all of these are. MUCH OBLIGED
Does Mr. Litz have this bullet library in his book, or is it available somewhere else? I shoot 7mm/162gr A-max's and have some other brands to tinker with and I would like to know what the G7 values for all of these are. MUCH OBLIGED
Re: At what range is g7 better then g1? Anyone k
Recon,
The G7 BC for the 7mm 162 grain Hornady Amax is: 0.307.
I'm happy to share some values, but if you want all 175 bullets:
http://www.appliedballisticsllc.com/index_files/Book.htm
-Bryan
Recon,
The G7 BC for the 7mm 162 grain Hornady Amax is: 0.307.
I'm happy to share some values, but if you want all 175 bullets:
http://www.appliedballisticsllc.com/index_files/Book.htm
-Bryan
Re: At what range is g7 better then g1? Anyone k
Recon Buy the book and CD its a great referance of data for a long time to come.
Bill
Recon Buy the book and CD its a great referance of data for a long time to come.
Bill
Re: At what range is g7 better then g1? Anyone k
I am positively going to get the book, I wasnt trying to weasle a specific G7 and not support Mr. Brian
, I was just wondering if the bullet library was in the book. I need all the help I can get getting my brain wrapped around all that happens from muzzle to target and from what I am gathering Mr. Brians book is a valuable reasource. Whats the best place to order it from?
I am positively going to get the book, I wasnt trying to weasle a specific G7 and not support Mr. Brian
