May 13, 2008
Barnes Bullets is in the process of reshooting its entire line of bullets to determine new ballistic coefficient (BC) values more useful to today’s shooters. Because accurate BC values are important, particularly for long range shooting, Barnes fires each bullet under tightly controlled laboratory conditions. The muzzle velocity, time of flight to target and distance to target then goes to a computer programmed to use these and other variables including temperature, humidity, altitude and barometric pressure to determine the actual BC of the bullet. Some manufacturers only compare their bullets to existing size and shape models to determine a theoretical BC. This theoretical method fails to take into account rifling marks inscribed in the bullet, muzzle yaw, actual bullet velocity and other important variables.
Barnes now measures BC values over 300 yards (they were formerly measured over a distance of 100 yards). Dr. Ken Oehler, of Oehler Research, Inc., suggests that BC values will probably predict trajectories at more than twice the distance over which the BC value was originally measured. Barnes feels measuring the BC over 300 yards will provide customers with data more useful for long range shooting out to 600 yards or more.
Over the past five years, Barnes has made slight changes to the geometry of many of its bullets, most notably in the shape of the ogive. Some fairly pronounced secant ogives have been changed to provide more tangent ogives. While slightly reducing BC values, this has significantly improved accuracy. BC values are also affected by multiple rings cut into the shanks of Triple-Shock X-Bullets.
Barnes is currently retesting all TSX bullets, and will post the new values on the company website (http://www.barnesbullets.com/) as they become available. Several new BC values already appear in the latest Barnes catalog. If you have questions about a specific bullet, please feel free to call 1-(800)-574-9200 or email tyh@barnesbullets.com.
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