Can you shoot lead bullets in a polygonal barrel?
When you fire a lead bullet in a polygonal rifled barrel, which has shallow hills and valleys instead of grooves and lands, the lead bullet isn’t gouged. Instead, the rifling squeezes down by the rifling, and the lead bullet will frequently “skip” over the hills. This leaves lead deposits throughout the barrel.
What is gain twist rifling?
“Gain-twist” refers to a form of barrel rifling where the twist rate gets tighter over the length of the barrel. For example, a gain twist barrel might start with 1:12″ twist and finish with 1:8″ twist.
Is polygonal rifling better?
Providing a better gas seal around the projectile as polygonal bores tend to have shallower, smoother edges with a slightly smaller bore area, which translates into more efficient seal of the combustion gases trapped behind the bullet, slightly greater (consistency in) muzzle velocities and slightly increased accuracy.
What is the purpose of polygonal rifling?
Polygonal rifling prohibits the examiner from measuring the width of land and groove impressions because the lands and grooves have a rounded profile instead of a well-defined rectangular profile. Polygonal rifling is most frequently observed in firearms marketed by Glock and Heckler & Koch.
Do lead bullets damage barrel?
And they do not damage or hurt the barrel any worse than jacketed bullets. At the slow velocities we use, barrel leading is rarely a problem when using a good quality hard cast bullet. Depending on the bullet hardness, serious leading doesn’t occur until you push it past 12- 1500 FPS.
What guns use polygonal rifling?
But a number of firearms manufacturers use polygonal rifling, most notably Glock, H & K, and Kahr. For years people have wondered about the effects of the different styles of rifling, and whether one or the other would offer specific advantages for accuracy or velocity from a given cartridge.
What does the twist rate on a barrel mean?
Twist rate is the ratio of inches of bullet travel down the barrel needed to rotate the projectile one full turn. In this case, the bullet makes one full rotation every seven inches. An illustration of different barrel twist rates. (
Why does rifling improve accuracy?
Rifling helps impart a spinning motion to a bullet when it’s fired. A spinning bullet is much more stable in its trajectory, and is therefore more accurate than a bullet that doesn’t spin. This is exactly why is is better to throw a football in a spiral.
What does rifling cause the projectile to do?
Rifling works by spinning the projectile about its axis, causing gyroscopic forces that spin-stabilize it throughout its flight; tighter rifling will spin a bullet faster, while looser rifling will spin a bullet slower.
Why is Glock polygonal rifling?
In reality, polygonal rifling is popular among law enforcement pistols and has been since before Glock was the mainstay. Polygonal rifling has shallower channels. Instead of using deep, square cuts, there are shallow cuts in the channel. This means that less gas can escape from the bullet without leaving the barrel.
What is Gain-twist rifling?
Gain-twist, or progressive rifling, increases the twist rate as the projectile moves down the bore. It is claimed that gain-twist rifling imparts less angular momentum to the bullet, thus reducing the tendency of the bullet to drift in the direction of the twist. Gain-twist rifling saw its first use during the War Between the States.
What is Gain twist on a rifle?
Gain-twist, or progressive rifling, increases the twist rate as the projectile moves down the bore. It is claimed that gain-twist rifling imparts less angular momentum to the bullet, thus reducing the tendency of the bullet to drift in the direction of the twist.
What is polygonal rifling used for?
Polygonal rifling was used in muzzleloaders (well, actually hexagonal, but what’s another angle among friends?) with lead bullets. Many a lead round has been shot out of polygonal barrels, and generally with reports of less leading. The ‘poly’ in polygonal just means there is more than one side, it doesn’t specify the number as ‘hexagonal’ does.
What is a 10 twist rifling?
Rifling is usually expressed as a twist rate; that is the length required to complete a full revolution along the horizontal access. For example, a firearm with a 10” twist has rifling that will turn the projectile 360 degrees in 10 inches, often expressed as a ratio, 1:10.