From the Berger website:
"Prior to 2008, all of Berger Bullets’ BC’s were calculated using a computer prediction. Early in 2009, we began measuring BC’s with live fire testing. As a result, Berger’s BC’s were updated and G7 BC’s were also made available.
This represented a dramatic improvement in the accuracy of performance data at that time. Since 2009, the BC’s assessed for Berger Bullets have not been updated.
As part of our ongoing effort to provide shooters with the best information possible,
Berger has been testing every lot of bullets produced for the last several years. The result is updated and highly accurate running averages of BC’s for recent production lots."
Source:
http://www.bergerbullets.com/update-of-berger-bullets-performance-data/
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From the Hornady website:
"Hornady originally published “800 yard”* average Ballistic Coefficient (BC) values for ELD-X and ELD Match bullets. This was done to provide the most usable BC from a trajectory prediction standpoint. Unfortunately many shooters did not understand that Hornady was listing a more useable “800 yard” BC while other manufacturers list “200 yard”* BCs. When doing pre-purchase research either on the web or at the store, the increased performance of the ELD Match and ELD-X bullets wasn’t always realized in a head-to-head BC comparison. Hornady will now publish “200 yard” (Mach 2.25 / 2,512 fps @ ICAO Standard Atmosphere**) G1 and G7 Ballistic Coefficient (BC) numbers for all ELD-X and ELD Match bullets. Mach 2.0 (2,233 fps @ ICAO Standard Atmosphere) and Mach 1.75 (1,954 fps @ ICAO Standard Atmosphere) BC values will also be available on the Hornady website (
www.hornady.com/BC). As Hornady moves the industry to drag coefficient based trajectory calculations for these types of projectiles (
www.hornady.com/4dof) the Ballistic Coefficient is becoming somewhat irrelevant except for those still using BC based trajectory calculators or when using BC as a rating criteria for bullet performance.
Ballistic Coefficient (BC) values at Mach 2.25 (2512 fps @ ICAO Standard Atmosphere) should be used when comparing to other published BC values within the industry. Ballistic Coefficient values at Mach 1.75 (1954 fps @ ICAO Standard Atmosphere), should be used when calculating trajectories for shooting beyond 600 yds. Ballistic Coefficient values at Mach 2.0 and 1.75 offer comparisons to other manufacturers that publish multiple BC’s based on velocity.
In addition to the change listed above, a select few ELD-X and ELD Match bullets initially had BC values that were determined from prototype bullets. As Hornady moved into production of these bullets, the BC value increased (a positive gain) due to the improvements in the manufacturing process from R&D to production machinery."
Source:
www.hornady.com/BC
