The Most Popular Caliber for an AR-15, Ranked

Choose the caliber you think is the most popular!

Author: Gregor Krambs
Updated on May 26, 2024 06:44
Choosing the right caliber for an AR-15 can significantly affect the performance and usability of this popular rifle, tailored to specific needs such as hunting, target shooting, or self-defense. A clear understanding of which calibers perform best under various conditions can help enthusiasts make informed decisions. However, with a variety of options available, it can be challenging for both new and experienced shooters to identify the most effective caliber without spending extensively on testing each one themselves. This is why a community-driven ranking of AR-15 calibers proves invaluable. It aggregates personal experiences and preferences, reflecting a wider spectrum of users. Here, users can vote for their preferred calibers based on their own experiences, and see how these stack up against the choices of others. Such collective insight not only aids in decision-making but also highlights trends and preferences within the shooting community.

What Is the Most Popular Caliber for an AR-15?

  1. 1

    6.5 Grendel

    The 6.5 Grendel is favored for its long-range accuracy and performance, bridging the gap between the .223 Remington and larger calibers.
    • Effective Range: 800 meters
    • Bullet Weight: 90 to 130 grains
  2. 2

    .458 SOCOM

    Developed for special operations, the .458 SOCOM offers powerful stopping power in a caliber that is compatible with the AR-15 platform.
    • Stopping Power: Significant compared to standard AR-15 calibers
    • Bullet Weight: 250 to 600 grains
  3. 3


    Originally used in the AK-47, the 7.62x39mm has been adapted to the AR-15 platform, offering a balance of power and cost-effectiveness.
    • Popularity: Widely used due to its availability and cost
    • Bullet Weight: 123 grains
  4. 4

    .224 Valkyrie

    The .224 Valkyrie was designed to offer superior long-range performance over the traditional .223/5.56 NATO in an AR-15 platform.
    • Effective Range: 1,300 yards
    • Bullet Weight: 60 to 90 grains
  5. 5

    223 Remington

    Closely related to the 5.56 NATO, the .223 Remington is a civilian round offering slightly less pressure, popular for sport shooting and hunting.
    • Interchangeability: Can be fired from 5.56 chambers
    • Velocity: Approximately 3,240 ft/s
  6. 6

    5.56 NATO

    The 5.56 NATO is the most popular and widely used caliber for AR-15 rifles, known for its versatility and military adoption.
    • Standard Military Round: Used by NATO countries
    • Velocity: Approximately 3,100 ft/s
  7. 7

    .300 Blackout

    The .300 Blackout is designed for improved performance at subsonic speeds with a suppressor, ideal for close quarters combat.
    • Supersonic and Subsonic: Versatile for different types of shooting
    • Bullet Weight: 110 to 220 grains
  8. 8

    .22 Nosler

    The .22 Nosler is designed to increase the performance of the AR-15 platform, offering a significant velocity increase over the .223 Remington.
    • Velocity Increase: Up to 20%
    • Bullet Weight: 55 to 77 grains
  9. 9

    9mm Luger

    The 9mm Luger conversion for the AR-15 is popular for those seeking a pistol caliber carbine with the ergonomics and modularity of the AR platform.
    • Recoil: Mild compared to rifle calibers
    • Ammunition Cost: Generally lower than rifle calibers
  10. 10

    .350 Legend

    The .350 Legend is a relatively new caliber designed for hunters, offering a straight-walled cartridge that is legal in more areas for deer hunting.
    • Hunting Regulation Compliance: Meets requirements in certain regions for deer hunting
    • Recoil: Lower than many other hunting calibers

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About this ranking

This is a community-based ranking of the most popular caliber for an AR-15. We do our best to provide fair voting, but it is not intended to be exhaustive. So if you notice something or caliber is missing, feel free to help improve the ranking!


  • 65 votes
  • 10 ranked items

Voting Rules

A participant may cast an up or down vote for each caliber once every 24 hours. The rank of each caliber is then calculated from the weighted sum of all up and down votes.


Additional Information

More about the Most Popular Caliber for an AR-15

6.5 Grendel
Rank #1 for the most popular caliber for an AR-15: 6.5 Grendel (Source)
The AR-15 is a versatile rifle. Many people choose it for its adaptability. One key feature is the variety of calibers it can use. The most popular caliber has a rich history and offers a balance of power and control.

This caliber became popular in the mid-20th century. It gained favor for its effectiveness in various settings. Its size allows for easy handling and good accuracy. This makes it a favorite among shooters and hunters alike.

In terms of performance, this caliber offers a good mix. It has enough power to be effective but not so much that it becomes hard to control. This balance is crucial. It ensures that shooters can maintain accuracy while still delivering enough impact.

The design of the AR-15 itself complements this caliber well. The rifle's structure helps manage recoil. This means that even with multiple shots, the shooter can stay on target. This synergy between the rifle and the caliber is a big reason for its popularity.

The availability of this caliber also adds to its appeal. Ammo is easy to find and often affordable. This makes it accessible for both new and experienced shooters. The widespread use of this caliber means that manufacturers produce it in large quantities. This helps keep costs down and ensures a steady supply.

Another factor is the versatility of this caliber. It performs well in various conditions. Whether in close quarters or at a distance, it remains effective. This adaptability makes it suitable for many uses. From sport shooting to hunting, this caliber meets the needs of many.

The military also uses this caliber, which speaks to its reliability. Its performance in demanding conditions has been tested and proven. This gives civilian users confidence in its capabilities. Knowing that it meets military standards adds to its credibility.

In recent years, this caliber has maintained its popularity. New shooters often start with it because of its manageable recoil and effectiveness. Experienced shooters appreciate its reliability and versatility. Its continued use in competitions and training also highlights its enduring appeal.

The popularity of this caliber is not just about performance. It also has a community of enthusiasts. Many forums and groups discuss its benefits and share tips. This sense of community helps new shooters learn and grow. It also keeps experienced shooters engaged and informed.

In conclusion, the most popular caliber for the AR-15 offers a mix of power, control, and versatility. Its history, performance, and availability make it a top choice. Whether for sport, hunting, or self-defense, it meets the needs of many. Its continued use by the military and civilian shooters alike speaks to its reliability. The community around it adds another layer of appeal. This caliber remains a cornerstone of the AR-15 experience.

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