Bullets Sizes and Types

Bullets: Sizes and Types [Guide + videos]

Guns Domain Editor August 6, 2024

0 5 7 minutes read

With tons of pictures, learn about the most common bullet sizes and calibers. Find out about the differences in bullet tip types such as FMJ and hollow point.

When I was first looking for a firearm, one of the biggest questions that came up was… which size bullet should I get?

The situation got worse when I looked at rifles.

We’ll cover some of the most popular calibers for handguns, rifles, and shotguns.

The strengths and weaknesses of both.

We’ll then go over bullet terminology, the different types (hollow-point, etc), shotgun shell size, and the breakdown of components in a round.

You’ll be a Bullet Pro by the end!

Bullet Size & Caliber

First!

“caliber”, in the context of guns, is the diameter of the barrel . This determines the size of the bullets that pass through the barrel. Usually in inch or millimeter…like.223 and 9mm for rifles.

For the sake of terminology, a “bullet” is the metal projectile. The entire cartridge is called a “cartridge”.

Here are some 9mm bullets that you may encounter.

Rimfire vs. Centerfire

First, there is the difference between rimfire cartridges and centrefire.

The primer of the rimfire cartridge is located in the rim, while that of the centerfire cartridge is found at the center. If you see a circular shape in the center, it’s a centrefire cartridge.

Rimfires can be purchased for a few cents per round. The most common caliber is the 22 LR.

This animation shows the firing pin hitting the primer of a cartridge.

Here are some casings that have been used for a centerfire and a rimfire. The primer strikes are visible on the rim of the rimfire, and in the center of the centerfire.

Common Bullet Calibers

It’s confusing because there are measurements in millimeters as well as inches.

A “grain” is also used as a weight unit to indicate the weight of gunpowder and bullets. One “grain” equals 7,000 grains, which is a pound.

Let’s now go through a few!

.22 LR

The bullet is mild and shoots well in pistols as well as rifles.

It is a good starter round for those who have never fired a gun before or are uncomfortable with noise.

Bullets are also a great way to learn sight pictures because they’re so cheap.

This is the most common caliber used by shooters. These are just a few steps above a pellet gun…especially when used in a rifle like the 10/22 shown below.

These are primarily used to take care of birds, rats, and snakes. Self-defense is possible, but may require a few shots.

We’re now getting to slightly larger sizes.

Personal, I wouldn’t use anything smaller than a pistol with a caliber of.380 for my primary weapon.

It is sometimes called a “9mm short” and has gained a lot of popularity in recent years thanks to all the “pocket guns” on the market.

The bullet is relatively low-recoiling and has good penetration at close range.

Massad Ayoob, a gun author, once said that the.380 is “a low-power round”. Some experts may say it is barely adequate while others may say it barely inadequate.

Even with good defensive rounds, the bullets and guns that fire them are not very effective beyond a close-ish distance.

9mm

To distinguish this round from other 9mm rounds, it is called the “9x19mm Parabellum”, or “9mm Luger”. For those who are in the know, you can just say “nine millimeter”, “nine mil”, or “nine mil”.

I like 9mm the best. If there were a round called “Goldilocks”, this would be my choice.

You can have fun shooting them. They are good for defence.

The 9mm bullet has the same diameter as bullets used in the.380 Special and.38 Special.

The only difference is the bullet weight and amount of gunpowder.

This is the standard round used by NATO and most police forces in the world.

This bullet size is also used by many other guns. Concealed carry is possible with a compact 9mm pistol. The magazines of most guns in this size range from 15 to 17 rounds.

Now, the popularity of Pistol Caliber Carbines has exploded. You can get the ergonomics and price of a 9mm rifle, but the hollowpoints.

The.40 caliber is the big, angry, whiskey drinking sister of the 9mm.

Originally developed for the FBI, this reduced 10mm cartridge has been popular ever since with other law enforcement agencies.

The 9mm cartridge has a lot more kick compared to other handgun cartridges. The bullet weights can range from 155 gr to 165 gr and even 180 gr.

The FBI has recently moved back to 9mm because agents can shoot faster and more accurately in 9mm than they can with.40 S&W.

45 ACP

This round was designed in 1904 for the 1911 pistol by John Browning. It has a long and interesting history.

This is a huge bullet with plenty of stopping power.

For years,.45 caliber rounds have been the choice of police officers and soldiers. They have proven themselves time and again. This bullet could be the subject of an entire article.

I can tell you that it is not the round for someone who has never fired a firearm before. It’s stopping power has been renowned for decades and it is popular among those who have a nostalgic attachment.

.38 Special and.357 Magnum

Most revolvers use the “thirty eight special”.

The recoil is manageable, but it can be a bit of a pain in the neck when used with a small or very lightweight revolver. The 9mm has a heavier, slower bullet, and a cartridge with more powder.

For a long time, the FBI issued this cartridge.

The.357 Magnum is the same round as the.357, except that it’s slightly longer.

Due to the size and pressure restrictions, you can safely fire a 38 Special in a 357 Magnum.

Bullet weights range from 110 to 130 to 158 grams.

7.62x39mm

This is the Soviet round that was used in the AK-47 rifle line.

The bullet has a weight of 123 grains, a moderate recoil and great knockdown.

The round is very affordable due to the availability of surplus military ammo. Check out the bullet size of this round compared to 5.56 next.

.223 / 5.56x45mm

The NATO “five-five-6” (mm), “two-two-3” Remington cartridge is almost identical in size to the “two-two-3” Remington (inch).

Because the 5.56 is more powerful than.223,.223 can be used in a 5.56, but 5.56 should not be used in a.223 gun.

The bullets weigh around 55 grams, and there is a light amount of recoil.

There is still a lot of debate about the effectiveness of the ammunition in the M16/M4/AR-15 rifles.

.308 / 7.62x51mm

The “three-oh eight” (inch) Winchester round is nearly the same size as the “seven six two” (mm), NATO round.

Mixing rounds is not recommended unless you have experience.

This is a very popular hunting round, with moderate recoil and high stopping power. A wide range of bullets are available, ranging from 150 to 208 grams.

Plus…one the most popular machine gun and sniper calibers for many militaries in the world.

It’s not really common among civilians but I had to include it here.

The bullet is huge, has a huge recoil and a range of over 2,000m. You don’t want it to hit you. The 660-grain bullet is pure stopping power.

The Barrett I had was fine because I was standing and it came with a suppressor.

Common bullet types & Terminology

Full Metal Jacket

This is the most popular type of bullet. It consists of a metal core made of soft metal such as lead, which is fully encapsulated in a metal of harder metal such as copper.

They can be rounded, flat, or a combination of the three. The wound channels are usually small and pass through the target.

The round is great for range, but not recommended for defensive use.

Hollow Point (HP),

Hollow points expand when they strike something. Because of their stopping ability, they are preferred by police officers, concealed weapons carriers, and homeowners.

Open Tip (OTM),

The fact that they have an open tip at the top makes them look hollow-pointed, but it is actually due to their manufacturing process. The openings of the bullets are too small for them to expand.

The bottom of the copper cup is used to create the regular FMJ bullets. Open-tip bullets work the other way around, where the bottom part of the cup becomes the tip of the bullet.

Open-tip bullets may also be referred to as Open Tip Match Bullets (OTM), since long-distance shooting enthusiasts prefer them. Open tip bullets are more consistent than FMJ because of the manufacturing process. When you are shooting from hundreds of yards, this is important!

Ballistic Tip

You get this when you combine the aerodynamics and stopping power of an FMJ. This hollow point is covered in (usually red or orange) plastic that mimics the profile of a FMJ.

These guns are used primarily for hunting and precision shooting.

You can see the bullets’ bottoms have been streamlined. The “boat-tail” design reduces drag when the bullet is flying through the air. HPBT stands for hollow point boat tail.

Soft Point

This is a previous attempt to achieve the ballistic benefits of an FMJ that has better expansion.

Soft point bullets have a portion of lead exposed at the tip. Softer lead is intended to flatten the bullet better when it hits a target. Ballistic tips are more effective than soft points.