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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.
If a 5.56×45mm NATO cartridge is loaded into a chamber intended to use .223 Remington, the bullet will be in contact with the rifling and the forcing cone is very tight. This generates a much higher pressure than .223 Remington chambers are designed for. [3] NATO chose a 178-mm (1-in-7) rifling twist rate for the 5.56×45mm NATO chambering.
The .223 WSSM was introduced in 2003 by the Browning Arms Company, Winchester Ammunition, and Winchester Repeating Arms Company. The .223 designation is a reference to the popular .223 Remington. It is currently the fastest production .22 caliber round in the world with muzzle velocities as high as 4,600 feet per second (1,402 meters per second).
If the rifling is a constant twist, then the rifling rides in the grooves engraved in the bullet, and everything is secure and sealed. If the rifling has a decreasing twist, then the changing angle of the rifling in the engraved grooves of the bullet causes the rifling to become narrower than the grooves. This allows gas to blow by, and loosens ...
The twist of the rifling must match the intended ammunition for best accuracy. Rifling with too slow a twist will not stabilize long bullets, causing them to precess in flight; at its worst, this can result in the bullets tumbling in-flight and keyholing, where bullets strike the target sideways. Too fast a twist can also be a problem, as it ...
A popular 7 mm hunting caliber bullet is actually .283 in diameter (7.2 mm), but wildcat cartridges using this caliber bullet in a 5.56 x 45 case have so far not been successful. There is an existing and well-developed use of hunting-rifle bullets in the .277 caliber (6.8 mm), introduced by Winchester as the 270 in 1925.
The 6×45mm cartridge provides better down range performance than the .223 Remington or the 5.56 NATO cartridges. The cartridge is currently offered by Les Baer in an AR rifle. The cartridge had been offered by Cooper Arms, Kimber and a few other rifle manufacturers in their rifles as a regular factory chambering for a period of time. [3]
The .300 Whisper (7.82x34mm) is a CIP standard [1] cartridge in the Whisper family, a group of cartridges developed in the early 1990s by J.D. Jones of SSK Industries.It was developed as a multi-purpose cartridge, capable of utilizing relatively lightweight bullets at supersonic velocities as well as heavier bullets (200–250 grains) at subsonic velocities.