9mm vs 45 Caliber: Unbelievable Comparison !

9mm vs 45 Caliber white and brown bottles on white table

June 10, 2023 / Comments (2)


9mm vs 45 Caliber. The 9mm calibre, also known as the 9x19mm Parabellum, has a rich history that dates back to its adoption by the German military in the early 1900s.

It quickly gained popularity due to its manageable recoil and high magazine capacity, becoming one of the most widely used pistol calibres today.

On the other hand, the .45 calibre, also known as the .45 ACP (Automatic Colt Pistol), has a storied past rooted in its adoption by the United States military.

Developed by John Browning, the .45 calibre gained a reputation for its stopping power and effectiveness in combat.

Understanding Caliber

Before diving into the specifics of 9mm and .45 caliber, it's essential to understand what caliber means. Caliber refers to the internal diameter of a gun's barrel and is often measured in inches or millimeters.

The size of the bullet corresponds to the caliber, with larger calibers generally accommodating larger bullets.

9mm: An Overview

The 9mm caliber, also known as 9x19mm or 9mm Parabellum, is one of the most widely used handgun calibers worldwide.

9mm vs. .45 caliber

It gained popularity due to its manageable recoil, higher magazine capacity, and widespread use by military and law enforcement agencies.

The 9mm is commonly found in various firearm platforms, from compact pistols to full-size handguns.

.45 Caliber: An Overview

The .45 caliber also referred to as .45 ACP (Automatic Colt Pistol), has a long-standing history and a dedicated following among firearms enthusiasts.

9mm vs. .45 caliber

Known for its larger bullet size and slower muzzle velocity, the .45 caliber is renowned for its stopping power and deep penetration. It has a distinct recoil characteristic and is often found in a full-size, semi-automatic pistol.

Difference Between 9mm and .45 Caliber Handguns

Bullet Size and Characteristics

The primary distinction between the 9mm and .45 caliber lies in their bullet size and ballistic characteristics. Understanding these differences is essential for evaluating their performance.

  • 9mm: The 9mm, also known as the 9x19mm Parabellum, features a smaller bullet diameter of 9mm (approximately 0.355 inches) and lighter-weight projectiles.
  • .45 Caliber: The .45 caliber, also known as the .45 ACP (Automatic Colt Pistol), has a larger bullet diameter of .45 inches (approximately 11.43mm) and heavier bullets.

Ballistic Performance

The variations in bullet size lead to differences in ballistics and performance between the 9mm and .45 caliber.

  • 9mm: The lighter bullets of the 9mm typically result in higher muzzle velocities, contributing to flatter trajectories and more energy downrange. The higher velocities can enhance accuracy and reduce the effect of bullet drop over longer distances.
  • .45 Caliber: The .45 caliber, with its heavier bullets, generally travels slower but delivers more power upon impact. The larger bullet diameter and greater mass of the .45 caliber bullet can potentially cause more tissue damage, which can be advantageous in self-defense scenarios.

Stopping Power

Stopping power, often a consideration in handgun selection is associated with a bullet's ability to effectively incapacitate a threat.

  • The .45 caliber has gained a reputation for its larger bullet size and heavier weight, often associated with enhanced stopping power. The larger diameter and greater mass of the .45 caliber bullet can potentially cause more tissue damage upon impact, increasing the likelihood of stopping an attacker.


When choosing between 9mm and .45 caliber handguns, it is crucial to consider factors such as personal preferences, shooting abilities, and the intended use of the firearm. Both calibers have their advantages and considerations.

  • The 9mm offers higher muzzle velocities, flatter trajectories, and lighter recoil, making it popular for its controllability and capacity in firearms. It is often favored for its ease of use and suitability for various applications, including self-defense and target shooting.
  • The .45 caliber, with its larger bullet size and potential for greater stopping power, is preferred by some individuals who prioritize maximum energy transfer and potential tissue damage. It is commonly used in self-defense scenarios where deep penetration and significant stopping power are desired.

Recoil and Control

Recoil is an important consideration when choosing a caliber, as it affects accuracy and the shooter's ability to control follow-up shots.

9mm vs. .45 caliber

The 9mm generally exhibits less recoil than the .45 Caliber, making it easier to handle for many shooters.

Personal preferences and shooting comfort can vary, and some individuals may prefer the .45 Caliber despite its increased recoil.

Magazine Capacity and Concealability

One advantage of the 9mm caliber is its higher magazine capacity. The smaller size of the 9mm cartridge allows for an increased round count, providing more ammunition in a single magazine.

This can be particularly beneficial in self-defense situations where every round matters.

Conversely, the .45 Caliber typically has lower magazine capacity due to the larger size of its rounds, impacting the number of rounds carried and potentially affecting concealment options.

Availability and Affordability

The availability and affordability of ammunition are important factors to consider. The 9mm enjoys widespread popularity, resulting in abundant ammunition supplies in the market.

This availability often translates into lower costs, making it more economical for practice and training.

In contrast, the .45 Caliber may be slightly more expensive due to lower demand and production volumes.

Range and Power

The range and power of a caliber depend on various factors, including bullet weight, muzzle velocity, and ballistic characteristics.

While the 9mm exhibits a flatter trajectory and higher muzzle velocity, the .45 caliber delivers heavier bullets with more energy upon impact.

Both calibers have proven effective within their intended ranges, and the choice between the two may depend on specific shooting requirements.


The 9mm and .45 caliber cartridges differ in bullet diameter. The 9mm, also known as 9x19mm Parabellum or 9mm Luger, has a bullet diameter of 9mm (0.355 inches).

Conversely, the .45 caliber, also called .45 ACP (Automatic Colt Pistol), features a larger bullet diameter of 11.43mm (0.45 inches).

9mm vs. .45 caliber

This variation in bullet size affects the overall performance characteristics of each caliber.

Stopping Power

The .45 caliber is renowned for its perceived stopping power due to its larger, heavier bullets.

The .45 ACP typically fires bullets in the 185 to 230-grain range, potentially creating wider wound channels and transferring more energy to the target upon impact.

This characteristic has historically made the .45 caliber a popular choice among users who prioritize stopping power and rely on it for self-defense or military applications.

On the other hand, the 9mm is known for its lower recoil and higher magazine capacity, providing more rounds for potentially multiple engagements.


Recoil is another significant difference between the two calibers. Generally, the .45 caliber exhibits more significant recoil than the 9mm.

The larger bullet diameter, combined with the increased energy generated by the .45 ACP, contributes to a more noticeable and sometimes sharper recoil.

In contrast, the 9mm offers lighter recoil, making it more manageable for shooters, especially those new to firearms or struggling with recoil.

Magazine Capacity

Magazine capacity is often a point of comparison between 9mm and .45 caliber handguns. Due to its smaller bullet diameter and overall cartridge dimensions, the 9mm typically allows for higher magazine capacity.

The smaller 9mm ammunition allows firearms to hold more magazine rounds than their .45 caliber counterparts.

This can be advantageous when a larger ammunition capacity is desired, such as in law enforcement or self-defense scenarios.

Terminal Performance and Penetration

Terminal performance refers to a bullet's ability to expand and transfer energy upon impact.

The 9mm and .45 Caliber have various bullet designs influencing their terminal performance, including hollow points and bonded bullets.

Factors such as expansion, penetration, and over-penetration risks must be considered when selecting ammunition for self-defense.

Please note that personal preferences, shooting skills, and intended use should guide the decision between the 9mm and .45 Caliber handguns.

It is recommended to test different firearms and ammunition types, seek professional guidance, and consider individual needs and requirements to make an informed choice.

Mythbusting and Debunking

Numerous myths and misconceptions surround the 9mm and .45 caliber debate. It is crucial to separate facts from fiction to make an informed decision.

Common myths include notions of superior stopping power or inadequate penetration, which can mislead potential firearm owners.

Evaluating credible information and seeking professional guidance is essential when debunking these myths.

Popular Firearms Chambered in 9mm

Numerous firearms are chambered in 9mm due to their widespread adoption and popularity. Some notable examples include:

  • Glock 19
  • Smith & Wesson M&P9
  • SIG Sauer P320
  • Heckler & Koch VP9
  • CZ P-10C

Popular Firearms Chambered in .45 Caliber

The .45 caliber has a dedicated following and is featured in various iconic firearms. Some popular choices chambered in .45 caliber include:

  • Colt 1911
  • Glock 21
  • Smith & Wesson M&P45
  • HK45
  • Springfield XD(M)

The Debate of Stopping Power: 9mm vs .45 Caliber

The question of which caliber, 9mm or .45 caliber, offers better-stopping power has sparked debates among firearms enthusiasts and experts.

Stopping power encompasses various factors, including bullet diameter, weight, velocity, and terminal ballistics.

.45 Caliber: The Perception of Stopping Power

The .45 caliber is often praised for its perceived stopping power due to its larger and heavier bullets.

The typical .45 ACP (Automatic Colt Pistol) cartridge fires bullets ranging from 185 to 230 grains, significantly heavier than those commonly used in 9mm ammunition.

The increased mass of .45 caliber bullets potentially leads to wider wound channels and the delivery of higher kinetic energy upon impact.

These factors can cause more substantial tissue damage and increase the likelihood of incapacitation.

Advantages of the 9mm Caliber

While the 9mm caliber utilizes lighter bullets, typically ranging from 115 to 147 grains, it compensates with higher velocities.

The lighter weight allows 9mm bullets to achieve higher muzzle velocities, resulting in flatter trajectories and potentially improved accuracy.

The increased velocity also contributes to reliable bullet expansion, especially with modern hollow point designs.

Adequate bullet expansion enhances effectiveness by creating larger wound channels and facilitating rapid incapacitation.

Factors Influencing Stopping Power

It is important to note that stopping power is influenced by various factors beyond caliber alone.

Shot placement, accuracy, bullet construction, and individual physiological factors of the target all play crucial roles in determining the effectiveness of a particular caliber.

Furthermore, bullet design and technology advancements have narrowed the gap between these calibers regarding terminal performance.

9mm vs. .45 caliber

Ultimately, the concept of stopping power is complex and influenced by numerous variables.

Both the 9mm and .45 caliber have proven track records in real-world self-defense encounters, and their effectiveness relies on shot placement, bullet selection, and individual proficiency.

When choosing between the 9mm and .45 caliber, it is crucial to consider factors such as recoil management, ammunition availability, magazine capacity, and personal shooting abilities.

Each caliber has strengths and weaknesses; neither can be universally declared superior.

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2 Responses to :
9mm vs 45 Caliber: Unbelievable Comparison !

  1. Jeff Smith says:

    Lots of good information, although it was repeated several times.

  2. Anonymous says:

    A 9mm won’t stop a crazed but a .45 will

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