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.