When using JBM Ballistics software, what is the correct drag factor or most accurate drag factor to use with let's say 185 grain Berger BT long range?
- Thread starter Tangodown911
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Re: JBM Ballistics drag factor?
In the drop down chart use:
Berger, 0.308 cal, 185 gr, Long Range BT (Litz)
This is the most up to date and accurate data available.
In the drop down chart use:
Berger, 0.308 cal, 185 gr, Long Range BT (Litz)
This is the most up to date and accurate data available.
Re: JBM Ballistics drag factor?
Yeah that's what I did and it seemed accurate. I was in discussion with a friend who insists on using the G7 factor because it is used for Boat Tail design bullets. when this is used the data drastically changes to unrealistic numbers. Thus it cant be correct. What drag factor is Litz using?
Yeah that's what I did and it seemed accurate. I was in discussion with a friend who insists on using the G7 factor because it is used for Boat Tail design bullets. when this is used the data drastically changes to unrealistic numbers. Thus it cant be correct. What drag factor is Litz using?
Re: JBM Ballistics drag factor?
Tangodown,
It's important to understand that when you change the drag function (G1, G7) that you input a numeric value that corresponds to that function. For example, a bullet that has a G1 BC of .500 will have a G7 BC closer to .256. If you enter .500 into the program, and just change the drag function to G7, the results will be 'non-physical' (BS). If you choose to use the G7 drag function, you have to know the G7 BC which is numerically different from the G1 BC.
Here's some more background reading on the subject:
http://02b0516.netsolhost.com/blog1/?p=62
Take care,
-Bryan
Tangodown,
It's important to understand that when you change the drag function (G1, G7) that you input a numeric value that corresponds to that function. For example, a bullet that has a G1 BC of .500 will have a G7 BC closer to .256. If you enter .500 into the program, and just change the drag function to G7, the results will be 'non-physical' (BS). If you choose to use the G7 drag function, you have to know the G7 BC which is numerically different from the G1 BC.
Here's some more background reading on the subject:
http://02b0516.netsolhost.com/blog1/?p=62
Take care,
-Bryan
Re: JBM Ballistics drag factor?
It may be worth noting that if you pick from the JBM bullet library a bullet with (Litz) behind it, it makes no difference what drag model you pick on the setup page, as the program uses the correct G7 BC for its calculations.
It may be worth noting that if you pick from the JBM bullet library a bullet with (Litz) behind it, it makes no difference what drag model you pick on the setup page, as the program uses the correct G7 BC for its calculations.
Re: JBM Ballistics drag factor?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bryan Litz</div><div class="ubbcode-body">Tangodown,
It's important to understand that when you change the drag function (G1, G7) that you input a numeric value that corresponds to that function. For example, a bullet that has a G1 BC of .500 will have a G7 BC closer to .256. If you enter .500 into the program, and just change the drag function to G7, the results will be 'non-physical' (BS). If you choose to use the G7 drag function, you have to know the G7 BC which is numerically different from the G1 BC.
Here's some more background reading on the subject:
http://02b0516.netsolhost.com/blog1/?p=62
Take care,
-Bryan </div></div>
Roger that. Thanks Bryan for the input. I will read on it further and you have pretty much cleared it up. I trust your numbers and always use them in the library. Thanks for what you do.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bryan Litz</div><div class="ubbcode-body">Tangodown,
It's important to understand that when you change the drag function (G1, G7) that you input a numeric value that corresponds to that function. For example, a bullet that has a G1 BC of .500 will have a G7 BC closer to .256. If you enter .500 into the program, and just change the drag function to G7, the results will be 'non-physical' (BS). If you choose to use the G7 drag function, you have to know the G7 BC which is numerically different from the G1 BC.
Here's some more background reading on the subject:
http://02b0516.netsolhost.com/blog1/?p=62
Take care,
-Bryan </div></div>
Roger that. Thanks Bryan for the input. I will read on it further and you have pretty much cleared it up. I trust your numbers and always use them in the library. Thanks for what you do.
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