The Anatomy of a Bullet

First off, if you're looking for reloading information, click here.

This would have been, more correctly, referred to as 'The Anatomy of a Round'. However, 'bullet' seems to flow better, so I hope you'll permit me this one bit of artistic license in the article's title.

A loaded round is a balance of four components:

• A bullet
• The case (usually brass, but it's called brass, even if it's made of aluminum or steel)
• Powder (there are many types, with a variety of burn rates and 'cleanness')
• Primer (the cap in the bottom, which ignites the powder)

Bullets

Bullets are weighed by the grain, which is defined as 1/7000th of a pound. A bullet which weighs 55 grains (typical for 223 caliber) weighs .0078571428 pounds. The sheer number of decimal points should make it obvious why bullet weights are expressed in grains. To add further confusion, bullets are frequently listed by caliber only, for rounds which are commonly expressed in millimeters. For example, the 6.8 SPC cartridge uses a .270 caliber bullet. It is expected that if you get set up to reload a caliber, you will learn the appropriate caliber designation for the bullets you're using.

Powder

There are many types, with a variety of burn rates and residue. Like bullets, powder is measured in grains, of which there are 7000 in a pound. Powder is typically sold by the pound.

Primers

Of these various elements, the primer is the least variable. There are only four sizes of primer - lare rifle, small rifle, large pistol, and small pistol. primers are generally inexpensive; a box of 5000 can be had for around 2 cents a primer. The main variation between primers of a certain size, is how 'hard' or 'soft' they are. Extremely soft primers are easy to detonate; hard primers require more force. it is possible but stupid to load soft primers into rifle rounds in order to result in fully automatic fire. If you've been looking for a way to remove a hand or a few fingers, this can be an effective way to do it when your gun explodes due to an out-of-battery discharge.

Caliber vs Millimeter

These are two different means of measuring the diameter of a bullet. A caliber is generally a fraction of an inch, while millimeters are, well millimeters. While these may seem to be precise numbers (7.62x39mm, for example), most of them actually aren't. 7.62x39mm rounds use .311 caliber bullets, whereas 7.62x51mm rounds use .308 caliber bullets.

What is a 'grain'?

A grain is 1/7000th of a pound. This is how both powder and bullets are weighed. Usually, when you see a box of ammunition, it will state the weight of the bullets in grains. However, the powder charge is usually not listed.

Hollowpoints, wadcutters, JHP (oh my!)

What you need to know about corrosive ammo

-- SeanNewton - 12 Aug 2006