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Thus the optimum rate of twist for this bullet should be approximately 12 inches per turn. The typical twist of .30-06 caliber rifle barrels is 10 inches per turn, accommodating heavier bullets than in this example. A different twist rate often helps explain why some bullets work better in certain rifles when fired under similar conditions.
The test results were obtained from many shots, not just a single shot. The bullet was assigned 1.062 lb/in 2 (746.7 kg/m 2) for its BC number by the bullet's manufacturer, Lost River Ballistic Technologies, before it went out of business. Measurements on other bullets can give totally different results.
The Pejsa model allows the slope factor to be tuned to account for subtle differences in the retardation rate of different bullet shapes and sizes. It ranges from 0.1 (flat-nose bullets) to 0.9 (very-low-drag bullets). If this slope or deceleration constant factor is unknown a default value of 0.5 is used.
It was designed in 1905 by London based gunmaker W.J. Jeffery & Co to duplicate the performance of the .450/400 Nitro Express 3-inch in bolt-action rifles. [7] The .404 Jeffery fired a bullet of .422 in (10.72 mm) diameter of either 300 gr (19 g) with a muzzle velocity of 2,600 ft/s (790 m/s) and muzzle energy of 4,500 foot-pounds force (6,100 ...
Bullet parts: 1 metal jacket, 2 lead core, 3 steel penetrator. Terminal ballistics is a sub-field of ballistics concerned with the behavior and effects of a projectile when it hits and transfers its energy to a target. Bullet design (as well as the velocity of impact) largely determines the effectiveness of penetration. [1]
The 7×64mm's rimmed sister cartridge, the 7×65mmR, is also very popular in Central Europe for the same reasons as the 7×64mm. The legal banning of ex-military service cartridges like the .308 Winchester , 7×57mm Mauser , 8×57mm I, 8×57mm IS and the .30-06 Springfield in countries like France and Belgium also promoted acceptance and use of ...
The FN-created cartridge was named "5.56×45mm NATO" with a military designation of SS109 in NATO and M855 in the U.S. [13] These new SS109 ball cartridges required a 228 mm (1-in-9 inch) twist rate while adequately stabilizing the longer L110 tracer projectile required an even faster, 178 mm (1-in-7 inch), twist rate.
The common rifling twist rate for this cartridge is 254 mm (1 in 10 in), 4 grooves, ... velocity drops off as bullet weight increases. This is particularly evident ...