What Is Subsonic Ammo? Everything You Need To Know

By Jim Johnson / September 1, 2017
What is subsonic ammo

Subsonic ammo is now more popular than in the past. No one can deny the power of this silent weapon which is sought widely by many Defense Departments and police forces. Not only it increases the power of the shot but it also reduces the loudness. However, many people still haven’t known clearly about this kind of silent weapon.

This below article will provide the basic information about “What is subsonic ammo” and all its properties.

What is subsonic ammo?

Most bullets create small sonic booms when they fly through the air and our ears will hear the sound “crack” loudly. To avoid this loudness, subsonic ammo is created to be shot at speeds less than the speed of sound (1,126 ft/s).

In short, anything with speed lower than 1,126 ft/s is subsonic. Thanks to this feature, subsonic ammo prevents the shockwave or above annoying “crack” sound, which affects the loudness of the shot.

Subsonic ammo often uses heavier bullet to hold back as much energy and momentum as possible at the lower velocities. Some special subsonic ammo is used without a silencer to take advantages of heavier bullet weights.

In many situations, it’s actually inconvenient to shoot supersonic ammo without ear protection, while a subsonic load with the same powder load can be absolutely noisier than the sound of this action. In reality, the subsonic ammo is useful for any situations from effective home defense to hunting.

What Is The Benefit Of Subsonic Ammo?

Lower the noise

The bullets will surely fly at low velocities to avoid breaking the sound barrier. Therefore, it creates no "crack" noise. Moreover, lessen the shooting sound also eliminates the use of a sound suppressor or called "silencer”.

Make the shot more powerful

Most subsonic ammo gains the right balance by using heavier bullet which contains much more energy when travelling at lower velocities. Although they are travelling slower than standard bullets, they can convey more force for the shot thanks to their retained energy.

One ideal example for this benefit of subsonic ammo is the legendary gun M1911 .45 ACP. It uses 230 grain ammunition which travels at velocities lower than 1,126 ft/s. The larger and heavier bullet will provide the shooter with a powerful and reliable pistol.

Provide superior covert and stealth capabilities

Do you know why military forces need subsonic ammunition?

The reason is subsonic ammo is considered “superior covert and stealth capabilities”. This benefit fits well with hunters. They’re really stealth forces thanks to less noise when shooting.

However, hunter should use subsonic ammo with a silencer because it may be just as loud as supersonic ammo which travels faster than the speed of sound. The speed at which a bullet flies will influence the maximum velocity of cracking sound as it travels through the air.

As a result, the combination of subsonic ammo with a silencer makes the shot smoother and quieter thanks to the lack of cracking sound. Traditional ammo can’t fit well with a silencer because the crack will still make noise.

What Is The Disadvantage Of Subsonic Ammo?

Besides the advantage of subsonic ammo, what's its disadvantage?

The incomplete silence:

Subsonic ammo does create less noise than full-velocity rounds, but is this true for all situations? The rifle actually still creates a noise like “bang” and it is not powerful enough for hunting in big areas.

Supersonic loads break the barrier of sound, which results in the resounding crack that gun enthusiasts enjoy so much. Subsonic loads travel below the sound barrier, and as such, the cracking sound will never occur. However, subsonic ammo is really an important weapon for many hunters and shooters.

  • Possibility of inaccuracy:

The gunpowder used for a subsonic bullet has to be in smaller quantity than for a normal bullet. Therefore, the subsonic bullet will be heavier. This makes the bullet go beyond from accuracy and not go as far as it should. Moreover, it creates lower pressure which makes it hard to get a clean burn of the propellant and results in rapid fouling.

Greater risk of jamming:

A bullet can't be too heavy because this can make the bullet be blocked up. Therefore, using subsonic bullets which are heavier than the others will cause a greater risk of jamming.

Tips For Using Subsonic Ammo

You should consider a “silencer”

Subsonic ammo is quieter than other bullets, but hardly silent. While subsonic ammo does eliminate the “crack” sound and does “bang” at the barrel of a firearm due to its lower velocity, it won’t make your rifle as silent as a mouse. Therefore, you should consider using a “silencer” in tandem with subsonic ammo to reduce the noise of gunfire to the lowest level.

  • Do not always shoot subsonic ammo

Subsonic ammo actually doesn't have enough pressure to make some semi-automatic rifles like the AR-15 operate correctly. The reason is they often don’t work correctly if they don’t have enough blowback.

Therefore, the subsonic bullet travels slowly and unstably. Of course, this impacts greatly on accuracy, even in shorter distances. Moreover, you'll often lose significant range because the bullet isn’t flying fast.

  • Choose subsonic ammo based on purposes

When choosing the appropriate subsonic ammo, you should base on your purpose. Heavier handgun and subsonic ammo are the better choice for home defense because it provides heavier bullets.

When subsonic ammo is equipped with a silencer, this combination is very effective for hunter in smaller areas. For larger area, you should look for more accurate, silent one which is also powerful enough to conquer animals.


Nowadays, using a suppressor provides much benefit for any firearm. Even you shoot with your favorite silencer, you won’t enjoy like the first time you shoot with subsonic ammo. Although it has many advantages as well as disadvantages, subsonic ammo is still a powerful tool for many shooters, not only for military purpose but also for a variety of purposes.

If you are going to shoot more silently, you surely have to use subsonic ammo. Consider combining with a silencer as well and you'll be impressed with the result!

About the author

    Jim Johnson

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