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Old 01-18-2011, 01:16 AM
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Sectional Density ... Ballistic Coefficient

Originally Posted by Sophia View Post
When I started comparing the ballistics of the 6.5mm-08 Remington (aka .260 Rem)
with the 7mm-08 Remington,

I think I got a glimpse into why the .260 Rem isn't more popular.
The 7mm-08 beats the 6.5mm version in every measure except SD.
Sectional Density and Ballistic Coefficient are closely linked.

Want Better Sectional Density?
Ballistic Coefficient is essentially a measure of air drag.

The higher the number the less drag,
and the more efficiently the bullet cuts through the air.

So for purposes of flying through the air efficiently,
the bigger the BC number the better.

264" (6.5mm) 120 grain, BC .433
.264" (6.5mm) 140 grain, BC .496
.277" (.270) 130 grain BT, BC .449
.284" (7mm) 145 grain, BC .457
.284" (7mm) 145 grain Match, BC .465
6.5 Creedmoor 140 gr A-MAX
Ballistic Coefficient .585
Sectional Density .287
6.5 x 55 Swedish Mauser 140 GR SST Superformance
Ballistic Coefficient .520
Sectional Density .287
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