Who invented rifling wiki

Even with present-day precision, a drilled bore will deviate from the desired axis by as much as several thousandths of an inch per foot. Such a runout is accommodated by drilling the bore as closely as possible to the axis of an oversize cylinder, centering the rough barrel on the axis of the bore-wherever it is-and then turning the outside diameter parallel. Gun makers did not have this convenience before the 18th century, when powered lathes became available.

Until then, gunsmiths dealt with the fact that they could only file long surfaces flat. They finished the outside of gun barrels by hand-filing them to an octagonal cross-section, a process that would be done today by indexing heads and milling machines.

Early gun makers were forced to rely upon a number of handicrafts. The first stage of barrel making involved blacksmithing. A flat rectangle of iron was formed by hammering it to a thickness a little greater than the wall thickness of a finished barrel.

It was then shaped into a tube by hammering the blank into an anvil that had a semi-cylindrical channel that was the outside diameter of a barrel. The bore was formed by continually rotating the blank on the anvil while hammering it around a mandrel smaller than the finished bore. A number of reheats were required, during which care was taken to keep the mandrel at a lower temperature than the plate to prevent it from being welded in place.

After forming it into a tube, the smith welded the long edges of the plate into a seam that ran the full length of the barrel. The rough bore, formed when the mandrel was removed, served as a pilot for drilling. It was this that ensured that the finished bore and barrel would remain concentric.

Since the forged bore was not large enough to allow use of a cannon's boring bar, a series of bits of increasing diameter were run through the barrel. Colonial Williamsburg in Virginia has a gunsmithing program in which craftsmen work with a replica of a Colonial barrel drill. One man turns the drill itself, which does not move axially, while another feeds the barrel into the drill. The barrel is constrained by an elegant system of guides. Chip removal required frequent extraction and reinsertion of bits.

In Europe, straightness was sometimes checked by running a taut wire down the barrel and sighting on it through the bore. Bends were removed by hammering straight. Remarkably, such a process produced a passable barrel. A variation on the usual forming technique was the Damascus barrel. A tube was formed by wrapping and hammer-welding strips of steel around a mandrel. The process substituted a series of helical welds for a single longitudinal one.

Such barrels were prized at one time because of the decorative effect that could be achieved by acid etching. They fell out of favor very abruptly when smokeless powders were introduced.

During the modern era most infantrymen carry some version of an assault rifle like the American M16 or the Russian AK These deadly weapons give today's soldiers firepower equal to dozens of Civil War veterans. Civilization Wiki Explore. Civilization VI. All Games. Explore Wikis Community Central. Register Don't have an account? Rifling Civ6.

Edit source History Talk 0. Do you like this video? Play Sound. Back to the list of technologies "Bolt actions speak louder than words. That way, he'll be barefoot and you'll be out of range. The throat is usually sized slightly larger than the projectile, so the loaded cartridge can be inserted and removed easily, but the throat should be as close as practical to the groove diameter of the barrel. Upon firing, the projectile expands under the pressure from the chamber, and obturates to fit the throat.

The bullet then travels down the throat and engages the rifling, where it is engraved, and begins to spin. Engraving the projectile requires a significant amount of force, and in some firearms there is a significant amount of freebore, which helps keep chamber pressures low by allowing the propellant gases to expand before being required to engrave the projectile.

Minimizing freebore improves accuracy by decreasing the chance that a projectile will distort before entering the rifling. 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 72 inches 1, mm , or slightly longer, although for a typical multi-purpose muzzleloader rifle, a twist rate of 1 in 48 inches 1, mm is very common.

The M16A2 rifle, which is designed to fire the 5. Civilian AR rifles are commonly found with 1 in 12 inches Rifles, which generally fire longer, smaller diameter bullets, will in general have faster twist rates than handguns, which fire shorter, larger diameter bullets. The first and traditionally most common method expresses the twist rate in the length required to complete one full projectile revolution in the rifled barrel.

This method does not give an easy understanding if a twist rate is relatively slow or fast when bores of different diameters are compared. The second method describes the length required to complete one full projectile revolution in calibers or bore diameters.

The third method describes the angle of the grooves relative to the bore axis in degrees. The last two methods have the advantage that they express the twist rate as a ratio and give an easy understanding if a twist rate is relatively slow or fast even when comparing bores of differing diameters. This shortcut uses the bullet's length, needing no allowances for weight or nose shape. The original value of C was , which yields a twist rate in inches per turn, when given the diameter D and the length L of the bullet in inches.

If an insufficient twist rate is used, the bullet will begin to yaw and then tumble; this is usually seen as "keyholing", where bullets leave elongated holes in the target as they strike at an angle. Once the bullet starts to yaw, any hope of accuracy is lost, as the bullet will begin to veer off in random directions as it precesses. Conversely, too-high a rate of twist can also cause problems.

The excessive twist can cause accelerated barrel wear, and coupled with high velocities also induce a very high spin rate which can cause projectile jacket ruptures causing high velocity spin stabilized projectiles to disintegrate in flight. Spin stabilized projectiles made out of mono metals can practically not obtain adequate flight and spin velocities to disintegrate in flight due to their spin rate. Undersized bullets also have problems, as they may not enter the rifling exactly concentric and coaxial to the bore, and excess twist will exacerbate the accuracy problems this causes.

Lastly, a bullet which is "overstabilized" will maintain the orientation it was fired at; a ballistic trajectory requires the gun to be aimed above the target, thus an overstabilized bullet at long range will be pointing upward, even though it is moving downward, resulting in an oblique impact and aerodynamic inefficiency.

Ideally, a spin stabilized bullet is stable enough to not tumble, but unstable enough to allow aerodynamic forces to cause the tip to always point in the direction of travel. A bullet fired from a rifled barrel can spin at over , rpm, depending on the bullet's muzzle velocity MV and the barrel's twist rate. The general formula for calculating the rpm of a rotating object may be written as.