of such bullets being stereotyped as weekend sportsmen rather than preci- sion shooters who will notice a slight inaccuracy while shooting their bullets; thus the manufacturers tend to be more precise with the ballistics of bullets for this type of customer. The Nosler Ballistic Tip bullet, the
most overestimated of all the designs considered in this study, had a 6.33% average overestimate. One of the more overestimated Ballistic Tip models is the 125-grain bullet in .308. One of the authors (MC) has shot this bullet for
a number of years in .308 Winchester and .30-06 and has found this bullet to be a reliable performer as a dual purpose deer and varmint load out to 250 yards, but noticed that the bullet experienced noticeably more drop and wind drift than expected when pressed into longer range use. Considering the differences in trajectories predicted from the Nosler and Litz BCs suggests why. For a muzzle velocity of 3,200 fps, 20 °F, 0% relative humidity, 29.92 in Hg at sea level, with a 200-yard zero, the Nosler G1 BC of 0.366 predicts a drop of
68.8", a wind drift of 37.5" in a 10 mph cross wind, and an impact velocity of 1,696 fps with an energy of 798 ft-lbs at 600 yards. The Nosler BC predicts a transition to subsonic at 999 yards. Under the same conditions, the Litz G1 BC predicts a drop of 73.5", a wind drift of 42.5", and an impact velocity of 1,582 fps at 600 yards, with impact energy of 694 ft-lbs. The Litz BC predicts a transi- tion to subsonic at 912 yards. To further investigate the possibil-
ity that Nosler is generating their BCs for marketing purposes rather than to best inform the shooter regarding bal- listic performance, the BCs of the Ac- cuBond line were compared with the Ballistic Tip line in cases where there was a Ballistic Tip bullet in the same weight and caliber listed in the Nosler Reloading Guide Number Four. There were seven Ballistic Tip bullets listed in the reloading manual of the same weight and diameter of the AccuBond bullets which were introduced several years later. It is notable that six of the seven AccuBonds list exactly the same BCs (to three significant digits) in spite of having different boat-tail angles and ogives than their Ballistic Tip counter- parts. What is the probability that six of the seven AccuBond bullets with Ballistic Tip counterparts were actually tested to have identical BCs? In con- trast, what is the probability that Nosler decided simply to list the BCs of the AccuBond as equal or greater than the Ballistic Tips for the AccuBonds with Ballistic Tips in the same diameter and weight regardless of what was actu- ally measured? The average BC to SD ratio for AccuBonds with Ballistic Tip analogues is 1.879 (five of seven above 1.9); in contrast, the average BC to SD ratio for AccuBonds in weights unique to that design is the more humble 1.788 (only two of 15 above 1.9). One wonders if Nosler felt free to advertise more accurate BCs for AccuBonds without Ballistic Tips to which to compare them.
BiBliography Courtney, Michael; Courtney,
Amy “Inaccurate specifications of bal- listic coefficients.” 2009. The Varmint Hunter Magazine. Litz, Bryan. “Applied Ballistics
for Long-Range Shooting.” Applied Ballistics LLC, 2009.
Page 106 Winter 2012
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