140gr nosler customs in 6.5 cal

[Swarovski1]

Hi all,has any of you used the titled bullets,how did they shoot out to 1000yds,they are ment to be 0.529 bc,not sure if the bc increases if velocity is above a certain speed,sierra show 2 velocity speeds,the 139gr scenar is 0.578 bc but above 2600fps they are 0.612 bc apparently,does anybody know if this is correct too,atb swaro

[DaveT]

Never used those specific bullets but the answer to your secondary question about BCs is 'YES' you will see different G1 BCs quoted at differing speeds... this makes it hard to use G1 values in a ballistics program unless that program will take all the values supplied.

 

If you can find a G7 BC for your bullet then go with that as it more closely aligns with the true drag values for the majority of modern bullet shapes.

 

Drop me a PM if you need a more detailed explanation of G1 vs G7 BC values.

[Swarovski1]

Hi dave.would u happen to know the g1 bc of this bullet at the higher velocity and what the velocity it changes from.atb swarovski

[Laurie]

Bryan Litz gives the 140gn CC an average G7 BC of 0.281. That compares to 0.313 for the 140gn Berger VLD, 0.303 for the same make LRBT, 0.301 for the 142gn Sierra MK, 0.285 for the 139gn Lapua Scenar.

 

So, it's the lowest BC of the bunch, but not much different from the popular 139gn Scenar.

 

For 1,000yd use, forget G1 BCs - bullet velocity changes so much over this distance and the BC value is so velocity affected, that any predicted results will be appreciably out - usually optimistically.

 

Berger Bullets has a free interractive ballistics program on its website:

 

http://www.bergerbullets.com/ballistics/

 

likewise JBM Ballistics

 

use the 0.281 value and choose the G7 model in the input page

[Swarovski1]

Bryan Litz gives the 140gn CC an average G7 BC of 0.281. That compares to 0.313 for the 140gn Berger VLD, 0.303 for the same make LRBT, 0.301 for the 142gn Sierra MK, 0.285 for the 139gn Lapua Scenar.

 

So, it's the lowest BC of the bunch, but not much different from the popular 139gn Scenar.

 

For 1,000yd use, forget G1 BCs - bullet velocity changes so much over this distance and the BC value is so velocity affected, that any predicted results will be appreciably out - usually optimistically.

 

Berger Bullets has a free interractive ballistics program on its website:

 

http://www.bergerbullets.com/ballistics/

 

likewise JBM Ballistics

 

use the 0.281 value and choose the G7 model in the input page

[Swarovski1]

Thank you very much laurie.just the info i was after.140gr nos customs ive got should b good for 1k shooting.is the lowest bc but only fractionly.i did expect scenars to be up with the vld's.will try them all in time and see what shoots best in my 6.5 06.atb swarovski