Twist Rate
For best performance, the barrel should have a twist rate sufficient to spin stabilize any bullet that it would reasonably be expected to fire, but not significantly more. Large diameter bullets provide more stability, as the larger radius provides more gyroscopic inertia, while long bullets are harder to stabilize, as they tend to be very backheavy and the aerodynamic pressures have a longer "lever" to act on. The slowest twist rates are found in muzzleloading firearms meant to fire a round ball; these will have twist rates as low as 1 in 60 inches (1,500 mm), or slightly longer, although for a typical multi-purpose muzzleloader rifle, a twist rate of 1 in 48 inches (1,200 mm) is very common. The M16A2 rifle, which is designed to fire the 5.56x45mm NATO SS109 ball and L110 tracer bullets, has a 1 in 7-inch (177.8 mm) or 32 calibers twist. Civilian AR-15 rifles are commonly found with 1 in 12 inches (304.8 mm) or 54.8 calibers for older rifles and 1 in 9 inches (228.6 mm) or 41.1 calibers for most newer rifles, although some are made with 1 in 7 inches (177.8 mm) or 32 calibers twist rates, the same as used for the M16 rifle. Rifles, which generally fire longer, smaller diameter bullets, will in general have faster twist rates than handguns, which fire shorter, larger diameter bullets.
Read more about this topic: Rifling
Famous quotes containing the words twist and/or rate:
“Talk to them about things they don’t know. Try to give them an inferiority complex. If the actress is beautiful, screw her. If she isn’t, present her with a valuable painting she will not understand. If they insist on being boring, kick their asses or twist their noses. And that’s about all there is to it.”
—John Huston (1906–1987)
“If we became students of Malcolm X, we would not have young black men out there killing each other like they’re killing each other now. Young black men would not be impregnating young black women at the rate going on now. We’d not have the drugs we have now, or the alcoholism.”
—Spike Lee (b. 1956)