Owning an AR-15 that shoots 9mm rounds makes sense for several reasons. For instance, since 9mm rounds cost less, you can have more fun at the gun range without worrying about your wallet. However, if you want the best accuracy and handling while shooting 9mm rounds, your gun barrel has to be the right length. Keep reading to discover the best barrel length for 9mm.

The Optimum 9mm Barrel Length Depends On Your Needs

The best barrel length for your 9mm gun is one that matches your shooting needs. For instance, if you want an AR-15 that you can easily carry around, an overly long barrel will make the gun heavy and less portable. However, if you want maximum accuracy and muzzle velocity for hunting or long-range shooting, you should go for a lengthier barrel.

Below are the most popular 9mm barrel lengths and who they fit:

  • 4.5 inches: The shortness of a 4.5-inch 9mm barrel makes it suitable for home defense because you can easily wield it within closed spaces. The length is also ideal if you want to use your AR-15 as a concealed weapon for self-defense.
  • 5.5 inches: Like a 4.5-inch barrel, a 5.5-inch 9mm barrel is suitable for home defense and use as a concealed weapon. However, compared to a 4.5-inch barrel, a 5.5-inch barrel offers slightly better velocity and accuracy.
  • 8 inches: You cannot go wrong with an 8-inch 9mm barrel if you want impressive efficiency and handling. The barrel isn’t long enough to make your gun unwieldy, and it delivers impressive bullet velocity for hitting targets at 100 yards. However, you will get the most accuracy at 50 yards.
  • 11 inches: The bullet velocity from an 11-inch 9mm barrel isn’t significantly higher than what an 8-inch barrel delivers. However, it’s still an excellent choice if you want a barrel that fires rounds with enough force to take down targets at 50 to 100 yards.
  • 16 Inches: A 16-inch 9mm barrel is long enough to carry various attachments that you may want to add to the handguard of your AR-15, such as lights and laser sights. Even better, the length offers maximum muzzle velocity to increase your chances of hitting targets at 100+ yards.

What to Consider When Choosing a Barrel Length for 9mm

Before choosing a barrel length, you should consider these factors that will affect how you can use your gun:

Maneuverability

Maneuverability refers to your ability to wield a gun and move around with it easily. The more maneuverable a gun is, the more agile you will be, and the easier it will be to pull, aim, fire, and track targets for follow-up shots.

Short barrel guns are more maneuverable because they are lighter and less likely to get caught on obstacles. If you want a gun that you can quickly draw or raise and easily wield in small spaces or close combat situations, a short or medium length (4 to 8 inches) barrel is your best choice.

Velocity

Velocity refers to the speed and force with which a bullet flies from a gun. A stronger velocity will enable a bullet to fly with more energy and speed. The increased energy will help the bullet stay accurate and reach further distances before gravity causes it to drop.

Longer barrels deliver the most velocity. If you are a hunter or long-range shooter, you should go for a long barrel that delivers the most velocity without compromising gun handling.

For instance, a 16-inch barrel can deliver impressive velocity when shooting 9mm rounds. However, if you go above 16 inches, the increase in velocity becomes less significant. Also, going above 16 inches will make your gun heavier and clumsier to handle because of the added weight and length from the overly long barrel.

Customization

You may want to customize your AR-15 with a flashlight, laser, front grip, and other accessories. However, since most accessories go on the hand guard, you will not have a lot of room for customization with a short barrel.

Also, if you intend on suppressing your AR-15, you should have a short or mid-length barrel. If you add a 6-inch suppressor to a long barrel, you risk making the gun unwieldy.

Concealment

The whole point of a concealed weapon is you can carry it without people noticing it. That will be hard to do if your AR-15 has a barrel over 8 inches long. However, if you have no intention of using your AR-15 as a concealed weapon, you can make the barrel as long as necessary to fit your shooting needs.

Recoil

A long barrel minimizes recoil because the barrel’s weight keeps the gun muzzle steady during firing. If you want to keep recoil to a minimum, the best barrel length for 9mm is 10 to 16 inches.

The Best 9mm Barrel Length Options When Running a Suppressor

Suppressing your AR-15 can improve your aim by reducing recoil. It can also protect your hearing by muffling gunfire noises and protect your eyes by minimizing muzzle flash when shooting in low light conditions.

However, as we’ve mentioned, putting a suppressor on a long barrel can make your gun clumsy to wield. If maneuverability is your priority, go for a 4 or 5-inch barrel because adding a suppressor will keep the barrel at around 10 inches.

Long-range shooters and hunters can go for an 11-inch barrel. Adding a suppressor to such a barrel will take it to about 16 inches, which is among the optimal lengths for superior velocity when shooting 9mm.

Common 9mm Barrel Length Questions

Here are answers to some of the most popular questions about the best barrel length for 9mm:

Does barrel length affect a 9mm?

Like every other ammunition, barrel length affects the performance of 9mm ammo. A long barrel improves accuracy by stabilizing a bullet and enabling it to fly on a flat trajectory. A long barrel also allows gunpowder to burn completely, generating more force to help a bullet fly further and faster. In summary, if you want to hit far-off targets with greater accuracy, you will need a long barrel.

How much does barrel length affect 9mm bullet velocity?

Barrel length significantly affects 9mm bullet velocity because a long barrel allows gunpowder to burn completely, generating more force to propel a bullet. However, 9mm bullet tests show that bullet velocity does not significantly increase after 17 inches.

How much does a 9mm drop at 100 yards?

How far a 9mm bullet will drop at 100 yards will depend on weather conditions, the bullet's weight, and the gun used to shoot the bullet. According to GunData.org, a 124gr American Eagle (Federal) Full Metal Jacket round fired in zero wind conditions will drop about 12 inches at the 100-yard mark.

Is a longer pistol barrel more accurate?

Yes, a longer pistol barrel is more accurate because the long barrel will help stabilize the bullet before it exits the muzzle, leading to a straighter flight. Also, the long barrel will generate more velocity, helping the bullet to fly with enough energy and speed to maintain its course and escape gravity.

Looking for a 9mm Barrel?

If you are a fan of 9mm ammunition because of its availability, affordability, and versatility, you will be happy to know that you can make your AR-15 9mm compatible. The process only requires replacing the barrel, bolt, buffer, muzzle device, and magazine with ones that work with 9mm ammo. Fortunately, you can easily get all these parts at our store and have them shipped to your doorstep.

Head to Ballistics Advantage today to order premium 9mm barrels and other AR-15 parts you need to optimize your firearm.