308 155 scenar bc?
- Thread starter EB-TAC
- Start date
Re: 308 155 scenar bc?
Here's some info from Bryan Litz/Allpied Ballistics. You'll be better off using the Avg. G7 BC value.
www.appliedballisticsllc.com/index_files/Lapua_Scenar.pdf
Here's some info from Bryan Litz/Allpied Ballistics. You'll be better off using the Avg. G7 BC value.
www.appliedballisticsllc.com/index_files/Lapua_Scenar.pdf
Re: 308 155 scenar bc?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EB-TAC</div><div class="ubbcode-body">can some one tell me the bc of the bullets,on lapua they say they are .460,on midway usa they say they are like .503,im confused </div></div>
Lapua has lowered their published BCs quite a bit. Kind of like Hornady, they were a generally high. I think it went .508>.460 which is a pretty big drop.
Chris
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EB-TAC</div><div class="ubbcode-body">can some one tell me the bc of the bullets,on lapua they say they are .460,on midway usa they say they are like .503,im confused </div></div>
Lapua has lowered their published BCs quite a bit. Kind of like Hornady, they were a generally high. I think it went .508>.460 which is a pretty big drop.
Chris
Re: 308 155 scenar bc?
Don't get hung up on a bullet's ballistic coefficient, at least not the G1 coefficient. Ballistic coefficients combine the effects of mass and drag into one number, so one bullet may have a higher ballistics coefficient than another simply because it is a heavier bullet.
In a May 16, 2011 Berger Bulletin, Bryan Litz wrote about the concept of “form factor” and how it could be used to analyze the efficiency and performance of a given bullet. The form factor is the sectional density of a bullet divided by its G7 ballistic coefficient. The G7 ballistic coefficient is used instead of the G1 because the G7 standard is a better match for the longer boattail type bullets most of us shoot, and should be more constant over a wider range of velocities, as compared to the G1.
The form factor measures how efficiently a bullet flies (drag), independent of its weight. Form factors of 1.000 or greater are bad; form factors of 0.999 to 0.950 are better; and form factors of 0.950 and below are the best.
Doing the math for the Lapua 155 Scenars (.308): 0.223 (sectional density) / 0.236 (G7 BC) = 0.987 (form factor). This means the drag of the 155 Scenar is less than the drag for the G7 standard. It is one of the more efficient .308 bullets.
So… this is another reason to shoot the 155 Scenars.
Don't get hung up on a bullet's ballistic coefficient, at least not the G1 coefficient. Ballistic coefficients combine the effects of mass and drag into one number, so one bullet may have a higher ballistics coefficient than another simply because it is a heavier bullet.
In a May 16, 2011 Berger Bulletin, Bryan Litz wrote about the concept of “form factor” and how it could be used to analyze the efficiency and performance of a given bullet. The form factor is the sectional density of a bullet divided by its G7 ballistic coefficient. The G7 ballistic coefficient is used instead of the G1 because the G7 standard is a better match for the longer boattail type bullets most of us shoot, and should be more constant over a wider range of velocities, as compared to the G1.
The form factor measures how efficiently a bullet flies (drag), independent of its weight. Form factors of 1.000 or greater are bad; form factors of 0.999 to 0.950 are better; and form factors of 0.950 and below are the best.
Doing the math for the Lapua 155 Scenars (.308): 0.223 (sectional density) / 0.236 (G7 BC) = 0.987 (form factor). This means the drag of the 155 Scenar is less than the drag for the G7 standard. It is one of the more efficient .308 bullets.
So… this is another reason to shoot the 155 Scenars.
Re: 308 155 scenar bc?
There are gobs of load data for that bullet. Just search for 155 scenar loads.
There are gobs of load data for that bullet. Just search for 155 scenar loads.
Re: 308 155 scenar bc?
I ended up using .5 for a BC for my Sako TRG 22 in 308, 155 lapua scenars and 47 gr of Varget.
You end up changing the BC and fps to match your real world dope. The BC effects the far end of the yardage (1000 yd) more and fps effects the close end (100 yd) of the yardage scale.
Use jbm ballistics to get in the ball park. And you have to account for altitude and temperature (density altitude)
I ended up using .5 for a BC for my Sako TRG 22 in 308, 155 lapua scenars and 47 gr of Varget.
You end up changing the BC and fps to match your real world dope. The BC effects the far end of the yardage (1000 yd) more and fps effects the close end (100 yd) of the yardage scale.
Use jbm ballistics to get in the ball park. And you have to account for altitude and temperature (density altitude)
Re: 308 155 scenar bc?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Squarenut</div><div class="ubbcode-body">Don't get hung up on a bullet's ballistic coefficient, at least not the G1 coefficient. Ballistic coefficients combine the effects of mass and drag into one number, so one bullet may have a higher ballistics coefficient than another simply because it is a heavier bullet.
In a May 16, 2011 Berger Bulletin, Bryan Litz wrote about the concept of “form factor” and how it could be used to analyze the efficiency and performance of a given bullet. The form factor is the sectional density of a bullet divided by its G7 ballistic coefficient. The G7 ballistic coefficient is used instead of the G1 because the G7 standard is a better match for the longer boattail type bullets most of us shoot, and should be more constant over a wider range of velocities, as compared to the G1.
The form factor measures how efficiently a bullet flies (drag), independent of its weight. Form factors of 1.000 or greater are bad; form factors of 0.999 to 0.950 are better; and form factors of 0.950 and below are the best.
Doing the math for the Lapua 155 Scenars (.308): 0.223 (sectional density) / 0.236 (G7 BC) = 0.987 (form factor). This means the drag of the 155 Scenar is less than the drag for the G7 standard. It is one of the more efficient .308 bullets.
So… this is another reason to shoot the 155 Scenars.</div></div>
buy the book
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Squarenut</div><div class="ubbcode-body">Don't get hung up on a bullet's ballistic coefficient, at least not the G1 coefficient. Ballistic coefficients combine the effects of mass and drag into one number, so one bullet may have a higher ballistics coefficient than another simply because it is a heavier bullet.
In a May 16, 2011 Berger Bulletin, Bryan Litz wrote about the concept of “form factor” and how it could be used to analyze the efficiency and performance of a given bullet. The form factor is the sectional density of a bullet divided by its G7 ballistic coefficient. The G7 ballistic coefficient is used instead of the G1 because the G7 standard is a better match for the longer boattail type bullets most of us shoot, and should be more constant over a wider range of velocities, as compared to the G1.
The form factor measures how efficiently a bullet flies (drag), independent of its weight. Form factors of 1.000 or greater are bad; form factors of 0.999 to 0.950 are better; and form factors of 0.950 and below are the best.
Doing the math for the Lapua 155 Scenars (.308): 0.223 (sectional density) / 0.236 (G7 BC) = 0.987 (form factor). This means the drag of the 155 Scenar is less than the drag for the G7 standard. It is one of the more efficient .308 bullets.
So… this is another reason to shoot the 155 Scenars.</div></div>
buy the book
Re: 308 155 scenar bc?
"buy the book"
No thanks, Andy. I'm gonna wait until the movie comes out. In the meantime... don't give away the ending.
"buy the book"
No thanks, Andy. I'm gonna wait until the movie comes out. In the meantime... don't give away the ending.
