Complete Guide to Bullets and Calibers

Have you ever wondered why a .308 caliber bullet and a .300 PRC can be the same size but act differently? It’s all about the details of firearm calibers and cartridges. Knowing these differences is key for both fans and pros. This “Complete Guide to Bullet Calibers” will simplify these differences, giving you a clear step-by-step look at calibers by the numbers.

For beginners, understanding what “caliber” means is vital. It’s about the barrel’s width and the bullet’s size. For example, a .308″ caliber means the bullet is bigger than a .22″ caliber firearm caliber explained. It’s essential to know the difference between caliber and cartridge. The caliber is just about the bullet size. But the cartridge includes the case, primer, propellant, and bullet. The caliber doesn’t tell you about the cartridge’s speed or power. Take the .308 Winchester and the .300 PRC, for instance. They’re the same caliber but have different cases, making them not the same in power.

Understanding Caliber and Cartridge Terminology

Understanding bullet calibers is a good idea for several reasons, particularly for those involved in shooting sports, hunting, law enforcement, and military operations. Firstly, the caliber of a bullet directly affects its performance, including its range, accuracy, and stopping power,

which are essential factors for effectively and safely using firearms. Although you may not need to be an expert, understanding the fundamentals can help you select the correct firearm for your intended use.

Different calibers are designed for specific purposes; for example, a small caliber like .22 LR is ideal for target shooting and small game hunting, while larger calibers like .308 Winchester or .50 BMG are used for big game hunting and long-range shooting. Additionally, knowing the correct caliber ensures the firearm’s and ammunition’s compatibility, preventing dangerous malfunctions. It also aids in legal compliance, as regulations often specify permissible calibers for various uses. Therefore, a comprehensive understanding of bullet calibers enhances safety, efficiency, and effectiveness in the use of firearms.

What is a Caliber?

Caliber is the diameter of a firearm’s barrel and the bullet it fires. It’s measured in both metric and U.S. standards, with the metric system used globally and the U.S. standard in America. Knowing these measurements is vital for matching ammunition with firearms.

Components of a Cartridge

A cartridge is the full unit of ammunition. It has four main parts: the bullet, casing, propellant, and primer. These parts work together to make the cartridge function. Even cartridges of the same caliber can differ in size and type of propellant, affecting their performance⁴.

Bullet Size vs. Cartridge Dimensions

Many people confuse bullet size with cartridge dimensions. Bullet size is the diameter of the projectile. Cartridge dimensions include the casing and propellant too. Understanding this difference is key to comparing calibers and how they work with firearms.

Rifle Caliber Dimensions

Understanding rifle caliber dimensions is key for both enthusiasts and professionals. It affects how well a firearm performs and its use. Knowing how to switch between rifle calibers and millimeters is crucial, especially with so many sizes out there.

Caliber to Millimeter Conversion Chart

It’s important to know how to switch from rifle caliber dimensions to millimeters for accuracy. Miniature-bore calibers are those 0.22 inches (5.6 mm) or smaller, and small-bore calibers go up to 0.32 inches (8.1 mm). Below is a table that shows the caliber to millimeter conversion for common rifle calibers. It helps both new and experienced shooters pick the right ammo. This guide is key for using the to compare sizes.

Table: Small Calibers

Table: Intermediate Calibers:

Table: Larger Calibers

Table: Additional Handgun Calibers

Key Rifle Calibers and Their Uses

Knowing the uses of different rifle calibers is also crucial. The .22 Long Rifle is great for hunting small game and target shooting because it has low recoil and is affordable⁶. The .223 Remington is good for hunting varmints and tactical use because it’s fast and has a flat path⁶. The .30-06 Springfield is versatile for hunting medium to large game, and the .50 BMG is for military and long-range shooting. These calibers show how their sizes affect their use in different situations.

Looking at less common calibers, like the 6.5 Creedmoor for long-range precision and the .338 Lapua Magnum for extreme distances, helps us pick the best caliber for our needs7. This knowledge is very useful in hunting, sports shooting, or tactical use.

Common Mistakes While Purchasing Rifle Ammunition

Using the wrong ammunition in a firearm can lead to serious and potentially catastrophic consequences. The most immediate danger is a significant increase in pressure within the firearm’s chamber, which can exceed the firearm’s design limits. This can cause the barrel to burst or the firearm to explode, leading to severe injuries or even death for the shooter and bystanders. Even if an incorrect cartridge doesn’t cause an immediate catastrophic failure, it can still result in improper chamber fit, leading to misfires, malfunctions, and jams, which can be dangerous in high-stress situations. Repeated use of the wrong ammunition can also cause excessive wear and tear on the firearm, reducing its reliability and lifespan. Ensuring that the correct ammunition is used is crucial for the firearm’s safety, performance, and longevity. With the AR-15 in particular, many magazines and receivers can fit different cartridges. To avoid the dangers of placing the wrong magazine and ammo in a firearm, some gun owners label their magazines with a color band.

Potentially Dangerous Situations Examples:

.223 Remington vs. 5.56x45mm NATO

• Dimensions: Both have a bullet diameter of .224 inches (5.69 mm) and similar overall case dimensions (5.7×44.7mm for .223 Remington and 5.56x45mm for NATO).
• Confusion: They look nearly identical and can often be loaded into the same firearms.
• Dangers: 5.56x45mm NATO rounds are typically loaded to higher pressures than .223 Remington. Firing 5.56mm in a .223 Remington chamber can lead to increased wear, potential damage to the firearm, and even catastrophic failure, potentially causing injury.

.308 Winchester vs. 7.62x51mm NATO

• Dimensions: Both have a bullet diameter of .308 inch (7.82 mm) and similar case dimensions (7.8×51.2mm for .308 Winchester and 7.62x51mm for NATO).
• Confusion: They can be used interchangeably in many firearms.
• Dangers: .308 Winchester cartridges are often loaded to higher pressures than 7.62x51mm NATO. Using .308 Winchester in a firearm designed for 7.62 NATO can result in excessive pressure, leading to possible damage to the firearm and injury to the shooter.

.300 AAC Blackout vs. 5.56x45mm NATO

• Dimensions: Both have a similar cartridge base diameter, but the .300 AAC Blackout has a shorter case length (7.8×34.7mm) than the 5.56x45mm NATO.
• Confusion: Both can be used in the AR-15 platform, leading to accidental mixing of ammunition.
• Dangers: Attempting to fire a .300 AAC Blackout round in a 5.56mm chamber can cause a catastrophic failure as the bullet may not properly chamber and could cause an overpressure situation, leading to firearm damage and potential injury.

Common Firearms That Can Accommodate Multiple Calibers

Some firearms are designed to accommodate multiple calibers, allowing shooters to use various types of ammunition. This flexibility can be advantageous for shooting activities, from target practice to hunting. However, it’s crucial to recognize that not all calibers can be safely interchanged, as variations in pressure and dimensions can lead to dangerous malfunctions or damage to the firearm. The following list highlights calibers commonly known to be used interchangeably in specific firearms, with a strong emphasis on the importance of confirming compatibility with the firearm manufacturer or through the firearm’s manual before attempting to use alternative ammunition. Always prioritize safety and verify the correct usage to ensure a safe and effective shooting experience.

List of Calibers That Can Commonly Be Used in the Same Firearms

• 223 Remington and 5.56x45mm NATO
  • Disclaimer: 5.56x45mm NATO rounds can often be safely fired in .223 Remington firearms, but not always the other way around due to higher pressure in 5.56 rounds. Always confirm with the manufacturer.
• .308 Winchester and 7.62x51mm NATO
  • Disclaimer: .308 Winchester can generally be used in 7.62x51mm NATO firearms, but the reverse can be problematic due to the pressure differences. Verify with the firearm’s manual or manufacturer.
• .357 Magnum and .38 Special
  • Disclaimer: Firearms chambered for .357 Magnum can safely fire .38 Special rounds, but .38 Special firearms cannot handle .357 Magnum rounds. Always check your firearm’s specifications.
• .44 Magnum and .44 Special
  • Disclaimer: .44 Magnum firearms can shoot .44 Special rounds, but not the other way around. Confirm with your firearm’s documentation.
• .22 LR and .22 Long/Short
  • Disclaimer: Many .22 LR firearms can also fire .22 Long and .22 Short rounds, but verify with your firearm’s manual to ensure compatibility.
• .45 Colt and .410 Bore (in certain firearms)
  • Disclaimer: Some revolvers and certain firearms are designed to handle both .45 Colt and .410 Bore shotshells. Confirm this with your firearm’s manufacturer before attempting.
• 9mm Luger and 9mm NATO
  • Disclaimer: They are generally interchangeable, but 9mm NATO has higher pressure. Check with the manufacturer to ensure your firearm can handle both.

Common Handgun Calibers Explained

Choosing the right handgun caliber is key. It helps you pick the best one for your needs, whether for self-defense, target shooting, or starting.

Popular Handgun Calibers

The 9mm Luger is a favorite for its good balance of speed and recoil. Its bullets weigh 115 to 147 grains, move at 950 to 1200 feet per second, and have 295 to 384 foot-pound energy. It’s also affordable, typically costing between $0.19 and $0.24 per round, making it great for all levels of shooters. Although ammo shortages can cause spikes in price, 9mm is typically stable.

The .45 ACP is great for those who want more stopping power. Its bullets weigh 185 to 230 grains, go at 830 to 1015 feet per second, and have energy of 333 to 423 foot pounds. It costs about $0.28 to $0.34 per round, making it a solid choice for home defense and carrying concealed.

The .40 S&W is a good middle option between the 9mm and .45 ACP. Its bullets weigh 155 to 180 grains, move at 900 to 1200 feet per second, and have 358 to 496 foot-pound energy. At $0.29 to $0.38 per round, it’s versatile and cost-effective.

Bullet Size and Common Uses

The .38 Special and .357 Magnum are great revolvers. The .38 Special is used for target shooting and protection. Bullets weigh 110 to 200 grains, move at 675 to 980 feet per second, and have 200 to 320 foot-pounds of energy. They cost between $0.32 and $0.40 per round.

The .357 Magnum has more power, with bullets traveling 1200 to 1500 feet per second and having an energy of 700 to 1050 foot-pounds. It’s suitable for hunting, protection, and target shooting and costs about $0.42 to $0.68 per round.

The .22 LR is perfect for beginners because of its light recoil, low cost (about $0.05 to $0.07 per round), and ease of use. Its bullets weigh 36 to 40 grains, move at 1080 to 1280 feet per second, and have 104 to 146 foot-pounds energy.

Knowing about these standard handgun calibers helps us pick the right one, whether we’re new or experienced.

Guide to Calibers by the Numbers, Which is Which

The U.S. uses a standard system for measuring gun ammo, but most of the world uses a metric system. This difference can sometimes confuse those interested in guns.

Calibers tell us the size of the bullets and the gun barrels. They can be in inches or millimeters. For example, .22, .25, .32, and .357 show the size of the outside of the bullet in inches. On the other hand, 9mm Luger and 10mm are used for automatic and semi-automatic handguns. Shotshells are measured in gauge, with lower numbers meaning a bigger diameter, like the 12 gauge.

Understanding gun calibers is easier when you know their size. The .22 long rifle is great for small game and stays accurate up to 75 to 85 yards. The .357 Magnum is better for bigger targets because it has more energy from its longer case and more gunpowder. Shotguns come in sizes like 10, 12, 16, and 20 gauge, each with a different barrel size.

For hunting medium-sized game like deer, picking the right caliber is key. Animals like deer need a certain amount of energy to be hit effectively¹¹. Choosing the right ammo for your hunt is important for both ethical hunting and success. So, picking a caliber that fits your target and distance is crucial.

There are many types of bullets, like SP, AP, BT, and BTHP, each with its use. The Russian 5.45 x 39mm and the U.S. 5.56mm ball round show how different calibers have different uses.

Special Considerations for Shotgun Calibers

Understanding shotgun gauges is crucial for selecting the correct ammunition and ensuring safe operation. Using the wrong gauge ammunition can result in poor performance or dangerous situations, such as barrel obstructions or firearm damage. Always verify the gauge marked on your shotgun and use matching ammunition for safe and effective shooting.

Gauge vs. Caliber

Shotguns have standard gauges like 10, 12, 16, 20, and 28. Gauge is determined by the number of lead balls of the shotgun’s bore diameter that make up one pound. The larger the gauge number, the smaller the bore diameter. This system helps standardize shotgun sizes and ensures compatibility between firearms and ammunition, promoting safety and performance in shooting sports and hunting.

The Guage Calculation

The bore diameter is measured to determine the gauge, and then a corresponding number of lead balls (each the same diameter as the bore) is calculated to weigh one pound. This means that the larger the gauge number, the smaller the

bore diameter. Conversely, a smaller gauge number corresponds to a larger bore diameter.

Examples:

• 12-gauge: If 12 lead balls of the bore size weigh one pound, the shotgun is a 12-gauge. This is one of the most common shotgun sizes.
• 20-gauge: If 20 lead balls of the bore size weigh one pound, the shotgun is a 20-gauge. This gauge is smaller in diameter than a 12-gauge.
• 28-gauge: If 28 lead balls of the bore size weigh one pound, the shotgun is 28-gauge. This is smaller than both 12-gauge and 20-gauge.

The Shotgun Gauge Exception

The .410 bore is often called a gauge but is actually a caliber because its diameter is .410 inches. Knowing the difference between gauge and caliber is key when picking shotgun ammo for different uses.

Shotgun Shell Length

Shotgun shells come in various lengths, and understanding these lengths is crucial for ensuring compatibility with your shotgun. The most common lengths for shotgun shells are 2 ¾ inches, 3 inches, and 3 ½ inches. Here’s an overview of different shell lengths and their compatibility:

Common Shot Shell Lengths:

1. 2 ¾ Inches:
   • Usage: This is the most standard shell length and is widely used for various purposes, including hunting, target shooting, and home defense.
   • Compatibility: Almost all shotguns are designed to accommodate 2 ¾-inch shells. They are generally the most versatile and readily available.
2. 3 Inches:
   • Usage: These shells are often used for hunting larger game or situations requiring more power and a larger shot payload.
   • Compatibility: Many modern shotguns are chambered to handle both 2 ¾-inch and 3-inch shells. However, checking the barrel or receiver markings is essential to confirm that your shotgun can safely fire 3-inch shells.
3. 3 ½ Inches:
   • Usage: These are the longest and most powerful shotgun shells, typically used for hunting large game and waterfowl due to their increased shot capacity and range.
   • Compatibility: Only shotguns specifically chambered for 3 ½-inch shells should be used to fire these. Using a 3 ½-inch shell in a shotgun not designed for it can be extremely dangerous.

Important Considerations for Compatibility:

• Chamber Length: The chamber of a shotgun is designed to accommodate specific shell lengths. Firing a shell longer than the chamber is designed for can cause excessive pressure, leading to potential firearm damage and personal injury.
• Shell Crimp: The length of a shotgun shell is measured after the shell has been fired and the crimp (the folded end of the shell) is open. A 3-inch shell, for example, will measure slightly shorter when unfired.
• Shotgun Markings: Always check your shotgun’s markings, usually found on the barrel or receiver, to determine the maximum shell length it can safely fire.

Important Disclaimer:

Before using any shotgun shells, always verify the shell length compatibility with your shotgun’s specifications. Refer to the shotgun’s manual or the markings on the barrel or receiver to confirm the maximum shell length it can safely handle. Using shells longer than what the shotgun is chambered for can result in excessive pressure, firearm damage, and serious injury. Safety should always be your top priority when handling firearms and ammunition.

Common Shotgun Gauges

Let’s look at the details of common shotgun gauges:

Choosing the right shot size is also important when picking ammo. For example, 12-gauge shotguns with #2, #4, and #6 shots are great for hunting mid-sized game. The 10-gauge is best for waterfowl with #BB, #1, and #2 shots. Knowing these options helps you make better choices for your shotgun.

Choosing the Right Caliber for Your Needs

When picking a caliber, consider what you’ll use it for, its cost, and what you like. The right caliber is key for hunting, protecting yourself, or shooting targets. Let’s look at some important factors and tips, especially for those new to it.

Steps for Selecting the Right Hunting Ammo

Know Your Firearm:

• Check the Caliber: The caliber of your firearm is typically marked on the barrel or receiver. Ensure you know this information, as it is critical for selecting the correct ammunition (e.g., .308 Win, .30-06, .270 Win).
• Read the Manual: The firearm’s owner’s manual provides specific recommendations on the types of ammunition that are safe and effective for use.

Understand Your Hunting Needs:

• Game Type: Different game requires different ammunition. Small game, medium game, and large game each have specific requirements for effective and humane hunting.
• Distance: Consider the typical shooting distances for your hunting. Longer distances may require bullets with higher ballistic coefficients and better long-range performance.

Bullet Type and Design:

• Expanding Bullets: For hunting, use bullets designed to expand upon impact, such as Soft Point (SP), Hollow Point (HP), or Ballistic Tip (BT). These bullets maximize energy transfer and cause more significant tissue damage, ensuring a humane kill.
• Controlled Expansion: Some bullets are designed for controlled expansion and deeper penetration, suitable for larger and tougher game (e.g., Partition, Bonded bullets).

Seek Expert Advice:

• Ask Store Staff: Reputable gun stores have knowledgeable staff who can help you choose the right hunting ammunition based on your firearm and intended game.
• Consult Experienced Hunters: Friends or mentors who are experienced hunters can provide valuable insights and recommendations.

Check Packaging Labels:

• Match Caliber: Ensure the caliber on the ammunition box matches the caliber marked on your firearm.
• Review Specifications: Check the bullet weight, type, and intended use listed on the box to confirm that it meets your hunting needs.

Use Trusted Brands:

• Quality Matters: Stick to well-known, reputable ammunition manufacturers like Federal, Winchester, Hornady, and Remington. Quality ammo is essential for reliable performance and safety.

Consider Bullet Weight:

• Appropriate Weight: The bullet weight should be appropriate for the game you are hunting. Heavier bullets generally offer better penetration and stopping power for larger game, while lighter bullets may be suitable for smaller game.

Hunting Ammo Disclaimer:

Always choose ammunition appropriate for your specific hunting needs and game type. Consult with experienced hunters, manufacturers’ guidelines, or ballistic experts to ensure you select ammunition with adequate knock-down power for a humane and effective hunt. Safety and ethical considerations should always guide your choice of hunting ammunition.

Tips for Beginners

For newbies, it’s important to choose calibers that are effective yet easy to manage. Go for calibers with less recoil, like the 9mm for handguns or .22 caliber for rifles. These choices make learning to shoot safer and more fun.

Also, consider the cost of ammo and where you can get it. .22 caliber ammo is cheaper and easy to find, making it a good practice choice. Bigger calibers, though more powerful, are pricier and harder to handle, especially for beginners.

Using this guide to the best calibers can help you pick one that fits your needs and goals. This way, you’ll have a better and more enjoyable time shooting.

Comparing Calibers for Different Applications

Choosing the right caliber is key for hunting, personal defense, and target shooting. Each caliber has its benefits and drawbacks for different uses. Let’s explore this topic further.

Hunting

When hunting, picking the right caliber is crucial for success and humane treatment of the game. The choice depends on the animal’s size and how far you’ll shoot. For example, .22 long rifle ammo is great for animals under 15 lbs and hits its mark up to about 75-85 yds.

.22 Magnum can reach up to 125 yds and is good for animals in the 15-50 lbs range. For bigger game like deer, a .308 Winchester is a top choice. It’s powerful and can handle animals from 51-300 lbs with a minimum of 800-1000 ft. lbs. of energy.

Personal Defense

You must balance factors like recoil, stopping power, and ammo availability for defense. The 9mm Luger and .45 ACP are popular for their effectiveness and manageable kick. The guide lists over 38 bullet sizes, including .380 ACP and .38 Special, which are reliable and easy to handle.

Bullet grain weight affects recoil, too. Heavier bullets make more recoil than lighter ones.

Target Shooting

Focus on accuracy and cost-efficiency when shooting targets. .22LR is great because it’s affordable and has low recoil, perfect for practice. On the other hand, 6.5 Creedmoor is chosen for its long-range accuracy and minimal drop, which is great for competitions.

.223 Remington and 5.56 NATO are also popular for their precision and versatility.

In conclusion, knowing the differences between calibers is crucial for making the right choice for hunting, defense, and target shooting. This knowledge helps you make informed decisions, improving your performance and safety in each area.

Ammunition Caliber and Bullet Weight

Bullet weight is measured in grains, with one grain equaling 1/7000th of a pound; bullet weight significantly impacts a bullet’s performance characteristics, including velocity, trajectory, penetration, and energy transfer. Heavier bullets, typically ranging from 150 to 180 grains for calibers like .30-06 Springfield, provide greater momentum and deeper penetration,

making them suitable for larger game such as deer, elk, or bear. Conversely, lighter bullets, often between 55 to 100 grains for calibers like .223 Remington, offer higher velocities and flatter trajectories, which are ideal for smaller game, varmints, or target shooting. The choice of bullet weight should be aligned with the intended use and game type to ensure effective and ethical hunting or accurate target shooting. Proper bullet weight selection enhances the shooter’s ability to achieve clean kills or precise hits, maintaining the shooting experience’s effectiveness and safety.

Understanding Bullet Grain

Here are some common bullet weights:

1. 9mm ammo comes in 115, 124, or 147 grains.
2. AR-15 bullets weigh between 40 to 70 grains.
3. The .45 ACP caliber often uses subsonic rounds.

Impact on Performance and Recoil

Bullet weight changes both performance and recoil a lot. Heavier bullets like the 147-grain type go slower but hit harder, making them good for hunting or self-defense. On the other hand, lighter bullets, like the 124 grain for 9mm, are faster and go farther, ideal for target shooting and less recoil.

But bullet weight isn’t the only factor that affects recoil. Velocity, cartridge load, and powder type also matter a lot. Starting with standard weights like 115-grain for 9mm or 55-grain for .223 Remington is a good idea for beginners. Lighter bullets in subsonic loads are best for suppressed guns, making them quieter.

In conclusion, knowing about bullet grain and its effect on performance and recoil helps choose the right ammo for your needs. This is true whether you’re hunting, defending yourself, or just shooting for fun.

Complete Guide to Bullets and Calibers Conclusion

In our guide, we’ve covered a lot of ground, from basic terms to comparing different calibers. This journey shows how important it is to know about firearms. Understanding the difference between metric and imperial systems and gauge and caliber in shotguns is key.

The energy a cartridge holds is more than just its size. Velocity is crucial, as seen in the .357 Maximum cartridge, which has up to 1900 joules of energy. This shows how increasing velocity greatly increases energy. Also, comparing European and British calibers shows us different naming and design systems, adding depth to our knowledge.

Knowing about bullet grain and the specifics of rounds, like the 5.56x45mm’s speed of 3100 ft/s, helps us make smart choices. This knowledge lets us pick the right caliber for our needs, improving performance and safety. As we conclude, remember that this guide is your go-to for understanding firearm calibers.

Complete Guide to Bullets and Calibers FAQs