Hornady B.C. question

[winmag]

Does anyone know why the 150gr Hornady SST in .277 cal says
.525 b.c. in 270 win
.525 b.c. in 270 wby
and says .486 b.c. in 270wsm?
Is this a typo?(Im using Hornady's 7th edition as my referance) or is it based on c.o.l. along with bullet diameter(.277), and sectional density(.279)? Im confused.

 

[7 loader]

Call Hornady they will set it strait if it is from the book. But the bc should be close to that #.

 

[Kiwi Nate]

Its got to be a typo. To have a BC of .486, it would have to have the same form factor as the Nosler Partition. I have set up a few clients with the 150 grain SST for longer range pig work. The BC of .525 as listed in Sierra I6 and the tables generated are correct in the field. Hope that helps you a bit.

 

[winmag]

Thanks, I figured it was a typo, but after re-reading''how to calculate b.c.'' I just got more confused as to how they came up with those two numbers for the same bullet. I didn't see as to how c.o.l. or speed could factor in AT ALL,seeing as how both 270 Win and 270Wby have the same B.C. rating on the 150gr SST Im right inbetween the two, so I figured Id throw it out there for someone smarter than me so I could get some insight. Must be a typo

 

[winmag]

Wrote an e-mail to Hornady. Waiting for reply.

 

[ZSteinle]

dont know if this has anything to do with it but the 6.5mm 140 amax B.C. changed after Mr. Litz's book came out. Went from .550 to .585 maybe they havent updated them all yet

 

[winmag]

Thank you. hmmmmmm, I wrote Hornady an e-mail on Sunday eve, but have not hered back as of yet. Ill post thier reply when I get one.

 

[winmag]

HORNADY replied. The SST (and IB as well) 150gr .277 bullett IS .525 B.C. they made a typo, and appologise for the inconvienence.