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Bullets; From Lead & Minie Ball to Nitrated Cellulose Powders, Parts, Spin Calculator & More

If not for the bullet, nobody would fear the gun. Bullets have come a long way since rocks were the primary projectile. Lead, easily cast, soft and dense was the ideal material for projectiles. The first projectile was lead balls, although firearms were not the first to use lead projectiles. Slingers in ancient and medieval times used lead projectiles.

Minie Ball During Civil War

The round ball ruled the military and sporting world until the introduction of rifling and the need to speed up the reloading process. Enter the Minié Ball, an elongated, conical bullet with a hollow base. This allowed the insertion and ramming of the projectile without having to wrap it in a patch like the round ball. The gases would expand the hollow skirt engaging the rifling. The US civil war and the Crimean war were fought with the Minié Ball being the primary projectile.

Nitrated Cellulose Powders

Black powder, a mixture of charcoal, potassium nitrate (saltpeter) and Sulphur was limited to velocities of under 1800 fps, and with the addition of antimony the lead was harder and created less lead fouling, (lead deposits in the barrel). But with the introduction of nitrated cellulose powders (smokeless) velocities climbed to the point that leading was becoming a significant problem, so the introduction of gilding metal, a copper-zinc alloy or copper washed mild steel jacket surrounding the lead core gave protection against lead fouling.

Bullet Parts; Meplat, Ogive, Base & More

Remember that the projectile is the bullet, and when you insert the bullet into a case with powder and primer you have a cartridge. The bullet has many parts. Much of our ballistic terms come from the French who were the pioneers of ballistic research. The rounded or flattened point is the meplat, meaning “flat”. The curvy part is the ogive, and the straight part is the body, as it is in contact with the rifling it is commonly referred to as the ‘bearing surface’. The back of the bullet is the base. Most handgun projectiles have flat bases while some rifle bullets have a tapered base called a ‘boat tail’ which gives the bullet some aerodynamic advantages over the conventional flat base.

Bullet Spin Calculator

The bullet must provide a seal preventing gas leakage around the bullet. Therefore, a .30 caliber bullet is actually .308” in diameter. Bullets must survive the passage down the barrel and flight through the air. And remember the bullet is spun for stability. At 1000 fps (feet per second) and 1:12 spin means the rotation of the bullet is 1000 revolutions per second(rps), or 60,000 revolutions per minute (rpm), at 3000 fps and a 1:7 twist the bullet is turning a significant rpm, about 308,571, typically in the military M16 class of rifles. The centrifugal forces are trying to rip the bullet apart. Indeed, bullets designed for the lower velocity calibers will explode in the air when loaded and fired in high velocity cartridges.

Construction of a Bullet

On arrival, the projectile will go to work. If punching paper, ringing a steel gong or knocking over steel silhouettes the bullet must just hang together. Competitive shooting demands high quality projectiles, but expansion is not an issue, only the ricochet potential on steel targets is an issue. Self-defense and hunting further complicate the matter of bullet construction. To be effective the bullet must deform or expand. It gets shorter but bigger than its constructed diameter, presenting a broader surface that reacts with the targets medium, improving the size and depth of the wound channel tearing, crushing and ripping apart tissue (muscle) shattering bone and disrupting the nervous system.

What Are Bullets Made Of?

Most bullets have a lead core surrounded by a copper-zinc alloy jacket. Some east European military bullets are mild steel, and some of these are copper washed, a thin copper plating with the copper being a ‘lubricating’ metal.
Many states have passed legislation prohibiting lead bullets leading to the development of the monolithic bullet made of solid copper, copper alloy, brass or bronze. Regardless of the material all hunting and self-defense pistol bullets need to expand to provide for humane hunting kills and to stop a violent aggressor in a self-defense situation. Bullet construction should provide the performance needed from punching through paper to downing large dangerous game animals. Shooting Range Industries offers custom shooting ranges here in the United States of America. Contact us to learn more today.

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