Page 45 - Curriculum Visions Dynamic Book

(Right) Cannon were made first in bronze and then iron and then bronze again.
of cast iron. Then it was discovered how to improve the bronze and make it stand up better to explosions, so cast bronze cannons came back into fashion.
Small arms, such as muskets, rifles, and pistols, were developed in the 15th century. At first they were built like miniature cannons, but the development
of better steels allowed them to follow a separate history. They were needed in wars by the millions. People also realized that making them out of identical parts would allow the guns to be repaired easily.
As a result, the construction of rifles and pistols
was standardized. This was the forerunner of the mass production system.
Bullets and shells
A bullet is a small projectile that is fired from a pistol, machine gun, or rifle. Larger-size (caliber) projectiles are called shells.
The first bullets were made by dropping molten lead down a tall tower. As it fell, it split up into tiny balls, reaching the ground as solid shot.
As a result of the way they were made, the first bullets were round. These bullets could not, however, be fired very accurately. To improve the accuracy, narrow corkscrew- shaped cuts were made in the inside of the gun barrel. This effect, called rifling, made the bullet spin as it moved and so travel in a straighter line. A projectile-shaped bullet works much better in these circumstances, and so round bullets were replaced by the modern ones from about 1825.
Most pistol bullets are made of a mixture of lead and antimony alloy enclosed in a case of copper or copper- plated steel. Rifle and machine gun bullets are made with steel cases.
Armor-piercing bullets have the lead replaced with hardened steel.
The lead inside the bullet gives the bullet momentum and so makes it move through the air without being significantly slowed by air resistance. The casing, or jacket of copper
or steel, ensures the soft lead interior does not splay out as it enters the target. If the casing is left off the front of the bullet, the lead deforms when it hits the target and makes
a much bigger wound. This kind of “expanding bullet” is outlawed by all nations for war.
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