Rifling History

[Top*Shot]

Whilst walking the dog this morning to blow away last nights cobwebs I was crossing a shallow river and something caught my eye.
I picked out of the water what I thought was a musket ball. When I examined it with a magnifying glass I can make out rifling which I think consists of 7 ridges and furrows. It has been slightly flattened on one side too by an impact with something not too hard.

When rifling was first used, how many grooves were originally used and can a ball be dated from such information ?

Yes ! For those who know me my wife is an archaeologist. But she knows nothing about guns or militaria. Come on guys educate me let me be the expert for once.

[robinghewitt]

Wouldn't be a 5/8" ball would it? That would be a Baker rifle, that Richard Sharpe bloke on TV

[delta1]

He was on TV this morning.

Maybe a ricochet?

[Jim McArthur]

What battles were ought in the area where you found it?

Jim

[Top*Shot]

What battles were ought in the area where you found it?

Jim

It was found near Ewloe Castle and I dont know of any battles there, although there were civil war battles nearby at Hawarden.

[robinghewitt]

They certainly had "screw barrel" pistols in the CW. There is the famous story telling how Prince Rupert announced the King's arrival by shooting the high weather cock as a sort of gong. Suspecting a fluke shot, Charles asked if he could do it again, so he pulled his second pistol...

...bang, bong

[Hunter_zero]

I picked out of the water what I thought was a musket ball. When I examined it with a magnifying glass I can make out rifling which I think consists of 7 ridges and furrows.

How COOL is that! I'd be well happy if I had found a musket ball. Don't know anything that can help you about rifling but I know that musket balls were around .50 cal

John

[robinghewitt]

When the army went to rifled muskets (other than the Baker, the Ferguson and that other thing that never really got off the ground), they stopped shooting round balls

7 grooves sounds like a Baker, but unless Top Shot tells us how big it is we must flounder

Civil war bores usually a tadge bigger than musket bore which eventually standardised at .75", OTOH matchlock shooters liked their balls sized for "rowling" in. Pistols were, of course, smaller.

[Top*Shot]

When the army went to rifled muskets (other than the Baker, the Ferguson and that other thing that never really got off the ground), they stopped shooting round balls

7 grooves sounds like a Baker, but unless Top Shot tells us how big it is we must flounder

Civil war bores usually a tadge bigger than musket bore which eventually standardised at .75", OTOH matchlock shooters liked their balls sized for "rowling" in. Pistols were, of course, smaller.

As the ball is not completely spherical anymore I took a few measurements and the mean diameter reading is 12.21 mm the largest reading was 12.34mm. As the ball was found in a river it may well have been eroded too. Does this help.

[lilguy43uk]

He was on TV this morning.

Maybe a ricochet?

Is he Irish?

[robinghewitt]

mean diameter reading is 12.21 mm the largest reading was 12.34mm

Not military then, unless someone rifled a volley gun

Probably a sporting gun. Curiously scales often work better than calipers because balls were sold by how many you got to the pound.

Lots of shotguns but very few sporting rifle shooters before the Victorian fad for deer stalking in Scotland and they didn't shoot ball. English deer were taken by horse and hound. I'd guess pioneer gentleman rifle shooter with a German Jaeger rifle import, the Germans liked to shoot patched ball from a .50

Or, maybe, as it was in a stream... Napoleonic refugee militia out shooting English frogs in practice for the real thing

[Lakey]

Looked this up on the net if it is of any use.

Rifling is the helix-shaped pattern in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy.

Rifling is described by its twist rate, which indicates the distance the bullet must travel to complete one full revolution, such as "1 turn in 10 inches" (1:10 inches), or "1 turn in 30 cm" (1:30 cm). A shorter distance indicates a "faster" twist, meaning that for a given velocity the projectile will be rotating at a higher spin rate.

A combination of the weight, length and shape of a projectile determines the twist rate needed to stabilize it – barrels intended for short, large-diameter projectiles like spherical lead balls require a very low twist rate, such as 1 turn in 48 inches (122 cm).[1] Barrels intended for long, small-diameter bullets, such as the ultra-low-drag, 80-grain 0.224 inch bullets (5.2 g, 5.56 mm), use twist rates of 1 turn in 8 inches (20 cm) or faster.[2]

In some cases, rifling will have twist rates that increases down the length of the barrel, called a gain twist; a twist rate that decreases from breech to muzzle is undesirable, as it cannot reliably stabilize the bullet as it travels down the bore.[3][4] Extremely long projectiles such as flechettes may require impractically high twist rates; these projectiles must be inherently stable, and are often fired from a smoothbore barrel.



[edit] History
Main article: Rifle
Muskets were smoothbore, large caliber weapons using ball-shaped ammunition fired at relatively low velocity. Due to the high cost and great difficulty of precision manufacturing, and the need to load readily from the muzzle, the musket ball was a loose fit in the barrel. Consequently on firing the ball bounced off the sides of the barrel when fired and the final direction on leaving the muzzle was unpredictable.

The origins of rifling are difficult to trace, but some of the earliest practical experiments seem to have occurred in Europe during the fifteenth century. Though while true rifling dates from the mid-15th century, it did not become common place until the nineteenth century.


[edit] Manufacture

Rifling in a French 19th century cannon.Most rifling is created by either:

cutting one groove at a time with a machine tool (cut rifling or single point cut rifling);
cutting all grooves in one pass with a special progressive broaching bit (broached rifling);
pressing all grooves at once with a tool called a "button" that is pushed or pulled down the barrel (button rifling);
forging the barrel over a mandrel containing a reverse image of the rifling, and often the chamber as well (hammer forging);
flow forming the barrel preform over a mandrel containing a reverse image of the rifling (rifling by flow forming)[5]
The grooves are the spaces that are cut out, and the resulting ridges are called lands[disambiguation needed]. These lands and grooves can vary in number, depth, shape, direction of twist (right or left), and twist rate (see below). The spin imparted by rifling significantly improves the stability of the projectile, improving both range and accuracy. Typically rifling is a constant rate down the barrel, usually measured by the length of travel required to produce a single turn. Occasionally firearms are encountered with a gain twist, where the rate of spin increases from chamber to muzzle. While intentional gain twists are rare, due to manufacturing variance, a slight gain twist is in fact fairly common. Since a reduction in twist rate is very detrimental to accuracy, gunsmiths who are machining a new barrel from a rifled blank will often measure the twist carefully so they may put the faster rate, no matter how minute the difference is, at the muzzle end (see internal ballistics for more information on accuracy and bore characteristics).


[edit] Construction and operation

Conventional rifling (left) and polygonal rifling (right).A barrel of circular cross-section is not capable of imparting a spin to a projectile, so a rifled barrel has a non-circular cross-section. Typically the rifled barrel contains one or more grooves that run down its length, giving it a cross-section resembling a gear, though it can also take the shape of a polygon, usually with rounded corners. Since the barrel is not circular in cross-section, it cannot be accurately described with a single diameter. Rifled bores may be described by the bore diameter (the diameter across the lands or high points in the rifling), or by groove diameter (the diameter across the grooves or low points in the rifling.) Differences in naming conventions for cartridges can cause confusion; for example, the .303 British is actually slightly larger in diameter than the .308 Winchester, because the ".303" refers to the bore diameter in inches, while the ".308" refers to the groove diameter in inches (7.70 mm and 7.82 mm, respectively.)

Despite differences in form, the common goal of rifling is to deliver the projectile accurately to the target. In addition to imparting the spin to the bullet, the barrel must hold the projectile securely and concentrically as it travels down the barrel. This requires that the rifling meet a number of tasks:[4]

It must be sized so that the projectile will swage or obturate upon firing to fill the bore.
The diameter should be consistent, and must not increase towards the muzzle.
The rifling should be consistent down the length of the bore, without changes in cross-section, such as variations in groove width or spacing.
It should be smooth, with no scratches lying perpendicular to the bore, so it does not abrade material from the projectile.
The chamber and crown must smoothly transition the projectile into and out of the rifling.
When the projectile is swaged into the rifling, it takes on a mirror image of the rifing, as the lands push into the projectile in a process called engraving. Engraving takes on not only the major features of the bore, such as the lands and grooves, but also minor features, like scratches and tool marks. The relationship between the bore characteristics and the engraving on the projectile are often used in forensic ballistics.


[edit] Twist rate
For best performance, the barrel should have a twist rate sufficient to 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 SS109 bullet, has a 1 in 7-inch (180 mm) twist. Civilian AR-15 rifles are commonly found with 1 in 12 inches (300 mm) for older rifles and 1 in 9 inches (230 mm) for most newer rifles, although some are made with 1 in 7 inches (180 mm) twist rates, the same as used for the M16. Rifles, which generally fire longer, smaller diameter bullets, will in general have higher twist rates than handguns, which fire shorter, larger diameter bullets.

George Greenhill, a mathematician at Emmanuel College, Cambridge, UK, developed a rule of thumb for use in calculating twist rates for a given lead-core bullet. The formula, named the Greenhill Formula in his honour, is:


where:

C = 150 (use 180 for muzzle velocities higher than 2,800 f/s)
D = bullet's diameter in inches
L = bullet's length in inches
SG = bullet's specific gravity (10.9 for lead-core bullets, which cancels out the second half of the equation)
The original value of C was 150, which yields a twist rate in inches per turn, when given the diameter D and the length L of the bullet in inches. This works to velocities of about 840 m/s (2800 ft/s); above those velocities, a C of 180 should be used. For instance, with a velocity of 600 m/s (2000 ft/s), a diameter of 0.5 inches (13 mm) and a length of 1.5 inches (38 mm), the Greenhill formula would give a value of 30, which means 1 turn in 30 inches (760 mm).


A Parrott rifle, used by both Confederate and Union forces in the American Civil War.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 also induce a very high spin rate which can cause high-velocity projectiles to disintegrate in flight. A higher twist than needed can also cause more subtle problems with accuracy: Any inconsistency within the bullet, such as a void that causes an unequal distribution of mass, may be magnified by the spin. 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, excessive spinning causes a reduction in the lateral kinetic energy of a projectile, thereby reducing its destructive power (the energy instead becomes rotational kinetic energy).

[manxteddy]

Hi Top*shot
I live across the Dee to you and shoot at Sealand.
I don't know when the Sealand ranges were built but maybe it's come from there at some time.
BP is shot there by some folk.
There was a battle at Ewloe where an English army was ambushed but that's before rifle arms.
GrAHAM