Go to Sierra Bullets web site then to their Match King bullets. All of their BC's are listed. Use their G1 value in Berger's software that's in the velocity range used; .490 for example for their 30 caliber 175 HPMK.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master